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diff --git a/doc/Develop.htm b/doc/Develop.htm deleted file mode 100644 index fe4036c33..000000000 --- a/doc/Develop.htm +++ /dev/null @@ -1,4823 +0,0 @@ -<!doctype html> -<html lang="en"> -<head> - <meta http-equiv="content-type" content="text/html; charset=utf-8"> - <meta name="viewport" content="user-scalable=yes, initial-scale=1, width=device-width"> - <link href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:200,200i,300,300i,400,400i,600,600i,700,700i,900,900i" rel="stylesheet"> - <link rel="shortcut icon" href="images/favicon.svg"> - <title>Information for Ghostscript Developers</title> - <link href="default.css" rel="stylesheet" type="text/css"> -</head> - -<body> - <header><div class="title"><a href="index.html"><h1 aria-label="title">Ghostscript documentation</h1><h2 aria-label="version"></h2></a></div><a href="Search.htm" aria-label="Search" id="searchSite"><div class="search"></div></a></header> - <main> - <article> - <div class="outer"> - - <div class="inner"> -<!--START EDITING HERE--> - -<h1>Information for Ghostscript Developers</h1> -<h2><a name="toc"></a>Table of contents</h2> -<ul class="toc"> - <li><a href="#Introduction">Introduction</a></li> - <li><a href="#Architecture">Architecture</a></li> - <li> - <ul> - <li><a href="#Design_goals">Design goals</a></li> - <li><a href="#Design_principles">Design principles</a></li> - <li><a href="#Large_scale_structure">Large-scale structure</a></li> - <li><a href="#Object_oriented_constructs">Object-oriented constructs</a></li> - </ul> - </li> - <li><a href="#File_roadmap">File roadmap</a></li> - <li> - <ul> - <li><a href="#Substrate">Substrate</a></li> - <li><a href="#Graphics_library">Graphics library</a></li> - <li> - <ul> - <li><a href="#Library_support">Support</a>, - <a href="#Paths">Paths</a>, - <a href="#Text">Text</a>, - <a href="#Images">Images</a>, - <a href="#Paint">Paint</a>, - <a href="#Clipping">Clipping</a>, - <a href="#Other_graphics">Other graphics</a>, - <a href="#Driver_support">Driver support</a>, - <a href="#FAPI_support_gx">Font API support</a> - <a href="#Visual_trace">Visual Trace</a> - </li> - </ul> - </li> - <li><a href="#Device_drivers">Device drivers</a></li> - <li> - <ul> - <li><a href="#Internal_devices">Internal devices</a>, - <a href="#PS_and_PDF_writers">PostScript and PDF writers</a>, - <a href="#High_level_devices">Other high-level devices</a>, - <a href="#Other_maintained_drivers">Other maintained drivers</a>, - <a href="#Contributed_drivers">Contributed drivers</a></li> - </ul> - </li> - <li><a href="#PostScript_interpreter">PostScript interpreter</a></li> - <li> - <ul> - <li><a href="#Main_program">Main program</a>, - <a href="#Data_structures">Data structures</a>, - <a href="#Stacks">Stacks</a>, - <a href="#Interpreter_loop">Interpreter loop</a>, - <a href="#Scanning_parsing">Scanning/parsing</a>, - <a href="#Standard_operators">Standard operators</a>, - <a href="#Non_standard_operators">Non-standard operators</a>, - <a href="#Interpreter_support">Interpreter support</a>, - <a href="#PostScript_code">PostScript code</a></li> - </ul> - </li> - <li><a href="#PDF_interpreter">PDF interpreter</a></li> - <li><a href="#PPD">PostScript Printer Description</a></li> - <li><a href="#Build_process">Build process</a></li> - <li> - <ul> - <li><a href="#Makefile_structure">Makefile structure</a>, - <a href="#dev_files">.dev files</a>, - <a href="#Generators">Generators</a>, - <a href="#Build_support">Support</a></li> - </ul> - </li> - <li><a href="#Utilities">Utilities</a></li> - <li> - <ul> - <li><a href="#Utilities_in_PostScript">Utilities in PostScript</a></li> - <li><a href="#Utility_scripts">Utility scripts</a></li> - </ul> - </li> - </ul> - </li> - <li><a href="#Memory_management">Memory management</a></li> - <li> - <ul> - <li><a href="#Memory_manager_architecture">Memory manager architecture</a></li> - <li> - <ul> - <li><a href="#Objects_vs_strings">Objects vs strings</a>, - <a href="#Structure_descriptors">Structure descriptors</a>, - <a href="#Garbage_collection">Garbage collection</a>, - <a href="#Movability">Movability</a>, - <a href="#Parent_hierarchy">Parent hierarchy</a>, - <a href="#Allocator_API">Allocator API</a> - </li> - </ul> - </li> - <li><a href="#Freeing_storage">Freeing storage</a></li> - <li> - <ul> - <li><a href="#Explicit_freeing">Explicit freeing</a>, - <a href="#Reference_counting">Reference counting</a>, - <a href="#Real_garbage_collection">(Real) garbage collection</a> - </li> - </ul> - </li> - <li><a href="#Special_implementations">Special implementations</a></li> - <li> - <ul> - <li><a href="#malloc">malloc</a>, - <a href="#Locking">Locking</a>, - <a href="#Retrying">Retrying</a>, - <a href="#Chunk">Chunk</a> - </li> - </ul> - </li> - <li><a href="#Standard_implementation">Standard implementation</a></li> - <li><a href="#PostScript_interpreter_extensions">PostScript interpreter extensions</a></li> - <li> - <ul> - <li><a href="#Refs">Refs (PostScript "objects")</a>, - <a href="#save_forgetsave_restore">save/.forgetsave/restore</a>, - <a href="#Stable_allocators">Stable allocators</a>, - <a href="#Interpreter_GC">Garbage collection</a></li> - </ul> - </li> - </ul> - </li> - <li><a href="#Portability">Portability</a></li> - <li> - <ul> - <li><a href="#Structural">Structural</a></li> - <li> - <ul> - <li><a href="#CPU_and_compiler">CPU and compiler</a>, - <a href="#Library_headers">Library headers</a>, - <a href="#Cross_platform_APIs">Cross-platform APIs</a>, - <a href="#Makefiles">Makefiles</a> - </li> - </ul> - </li> - <li><a href="#Coding">Coding</a></li> - <li> - <ul> - <li><a href="#Explicit_dependencies">Explicit dependencies</a>, - <a href="#Implicit_dependencies">Implicit dependencies</a></li> - </ul> - </li> - <li><a href="#Platform_specific_code">Platform-specific code</a></li> - </ul> - </li> - - <li><a href="#Troubleshooting">Troubleshooting and debugging</a></li> - <li><a href="#Profiling">Profiling</a></li> - <li> - <ul> - <li><a href="#ProfilingMSVC6">Profiling with Microsoft Developer Studio 6</a></li> - </ul> - </li> -</ul> - - -<!-- [1.2 end table of contents] =========================================== --> - -<!-- [1.3 begin hint] ====================================================== --> - -<p>For other information, see the <a href="Readme.htm">Ghostscript -overview</a>. - -<!-- [1.3 end hint] ======================================================== --> - -<hr> - -<!-- [1.0 end visible header] ============================================== --> - -<!-- [2.0 begin contents] ================================================== --> - -<h2><a name="Introduction"></a>Introduction</h2> - -<p> -This document provides a wealth of information about Ghostscript's -internals, primarily for developers actively working on Ghostscript. It is -primarily <strong>descriptive</strong>, documenting the way things are; the -companion <a href="C-style.htm">C style guide</a> is primarily -<strong>prescriptive</strong>, documenting what developers should do when -writing new code. - -<p> -THIS FILE IS A WORK IN PROGRESS. MANY SECTIONS ARE PLACE-HOLDERS. -<hr> -<h2><a name="Architecture"></a>Architecture</h2> - -<h3><a name="Design_goals"></a>Design goals</h3> - -<p> -Ghostscript has the following high-level design goals (not listed in order -of importance): - -<ul> -<li>Functionality -<ul> -<li>Ability to interpret the current PostScript and PDF languages, as -defined (and occasionally, in the case of conflict, as implemented) by -Adobe. -<li>Ability to convert PostScript to and from PDF, comparable to -Adobe products. -<li>Ability to produce output for a wide range of resolutions (from -TV-resolution displays to imagesetters) and color models (black and white, -multilevel gray, bilevel or multi-level RGB and CMYK, 6- or 8-color -inkjet printers, spot color). -</ul> -<li>Performance -<ul> -<li>Ability to render PostScript and PDF with commercial-quality performance -(memory usage, speed, and output quality) on all platforms. -<li>Specifically, ability to render PostScript effectively in embedded -environments with constrained RAM, including the ability to put the code and -supporting data in ROM. -</ul> -<li>Licensing -<ul> -<li>Licensing that supports both the Open Source / Free software communities -and a commercial licensing business. -<li>Freedom from licensing restrictions or fees imposed by third parties. -</ul> -<li>Other -<ul> -<li>Easy source portability to any platform (CPU, operating system, and -development tools) that has an ANSI C compiler. -<li>Support for writing new interpreters and new drivers with no change to -any existing code; specifically, ability to support PCL 5e, PCL 5c, and PCL -XL interpreters, and the ever-changing roster of inkjet printers. -</ul> -</ul> - -<p> -These goals often conflict: part of Ghostscript's claim to quality is that -the conflicts have been resolved well. - -<h3><a name="Design_principles"></a>Design principles</h3> - -<p> -Part of what has kept Ghostscript healthy through many years of major code -revisions and functional expansion is consistent and conscientious adherence -to a set of design principles. We hope the following list captures the most -important ones. - -<h4>Non-preemption</h4> - -<p> -Ghostscript is designed to be used as a component. As such, it must share -its environment with other components. Therefore, it must not require -ownership of, or make decisions about, inherently shared resources. -Specifically, it must not assume that it can "own" either the locus of -control or the management of the address space. - -<p> -Not owning control means that whenever Ghostscript passes control to its -caller, it must do so in a way that doesn't constrain what the caller can do -next. The caller must be able to call any other piece of software, wait for -an external event, execute another task, etc., without having to worry about -Ghostscript being in an unknown state. While this is easy to arrange in a -multi-threaded environment (by running Ghostscript in a separate thread), -multi-threading APIs are not well standardized at this time (December 2000), -and may not be implemented efficiently, or at all, on some platforms. -Therefore, Ghostscript must choose between only two options for interacting -with its caller: to <em>return</em>, preserving its own state in data -structures, or to <em>call back</em> through a caller-supplied procedure. -Calling back constrains the client program unacceptably: the callback -procedure only has the options of either returning, or aborting Ghostscript. -In particular, if it wants (for whatever reason) to multi-task Ghostscript -with another program, it cannot do so in general, especially if the other -program also uses callback rather than suspension. Therefore, Ghostscript -tries extremely hard to return, rather than calling back, for all caller -interaction. In particular: - -<ul> - -<li>For callers that want to pass input to Ghostscript piece by piece, -Ghostscript returns with an <code>gs_error_NeedInput</code> code rather than -using a callback. This allows the caller complete flexibility in its -control structure for managing the source of input. (It might, for example, -be generating the input dynamically.) - -<li>In the future, the same arrangement should be used for input from -<code>stdin</code> and output to <code>stdout</code> and -<code>stderr</code>. - -<li>Likewise, scheduling of Ghostscript's own threads (contexts), currently -done with a callback, should be done with suspension. The Display -Ghostscript project (GNU DGS) is working on this. - -</ul> - -<p> -The one area where suspension is not feasible with Ghostscript's current -architecture is device output. Device drivers are called from deep within -the graphics library. (If Ghostscript were being redesigned from scratch, -we might try to do this with suspension as well, or at least optional -suspension.) - -<p> -Not owning management of the address space means that even though -Ghostscript supports garbage collection for its own data, it must not do any -of the things that garbage collection schemes for C often require: it must -not replace 'malloc' and 'free', must not require its clients to use its own -allocator, must not rely on manipulating the read/write status of memory -pages, must not require special compiler or run-time support (e.g., APIs for -scanning the C stack), must not depend on the availability of -multi-threading, and must not take possession of one of a limited number of -timer interrupts. However, in order not to constrain its own code unduly, -it must also not require using special macros or calls to enter or leave -procedures or assign pointers, and must not constrain the variety of C data -structures any more than absolutely necessary. It achieves all of these -goals, at the expense of some complexity, some performance cost (mostly for -garbage collection), and some extra manual work required for each structure -type allocated by its allocator. The details appear in the <a -href="#Memory_management">Memory management</a> section below. - -<h4>Multi-instantiability</h4> - -<p> -From many years of experience with the benefits of object-oriented design, -we have learned that when the word "the" appears in a software design -- -"the" process scheduler, "the" memory manager, "the" output device, "the" -interpreter, "the" stack -- it often flags an area in which the software -will have difficulty adapting to future needs. For this reason, Ghostscript -attempts to make every internal structure capable of existing in multiple -instances. For example, Ghostscript's memory manager is not a one-of-a-kind -entity with global state and procedures: it is (or rather they are, since -Ghostscript has multiple memory managers, some of which have multiple -instances) objects with their own state and (virtual) procedures. -Ghostscript's PostScript interpreter has no writable non-local data -(necessary, but not sufficient, to allow multiple instances), and in the -future will be extended to be completely reentrant and instantiable. The -device driver API is designed to make this easy for drivers as well. The -graphics library is currently not completely reentrant or instantiable: we -hope this will occur in the future. - -<h4>Late configuration binding</h4> - -<p> -Ghostscript is designed to make configuration choices as late as possible, -subject to simplicity and performance considerations. The major binding -times for such choices are compilation, linking, startup, and dynamic. - -<ul> - -<li>Compilation binds only CPU and compiler characteristics (including data -type size, presence of floating point hardware, and data alignment), and -whether the code will be used for production, debugging, or profiling. - -<li>Linking binds the choice of what features and device drivers will be -included in the executable. (Work is underway to make the choice of drivers -dynamic.) - -<li>Startup binds essentially nothing. Almost every option and parameter -that can appear on the command line can also be changed dynamically. - -<li>The selection of output device, all parameters associated with the -device, the selection of debugging printout and self-checking (in debugging -configurations), the macro-allocation of memory, and almost all other -operational parameters are dynamic. - -</ul> - -<p> -In addition, a number of major implementation decisions are made dynamically -depending on the availability of resources. For example, Ghostscript -chooses between banded and non-banded rendering depending on memory -availability. - -<h3><a name="Large_scale_structure"></a>Large-scale structure</h3> - -<p> -At the largest design scale, Ghostscript consists of 4 layers. Layer N -is allowed to use the facilities of all layers M <= N. - -<ol> - -<li>The bottom layer is called the <a href="#Substrate">substrate</a>. It -includes facilities like memory management, streams, fixed-point arithmetic, -and low-level interfaces to the operating system. The substrate is written -in C, with a little C++ and/or assembler code for some platforms. - -<li>The layer above the substrate is the graphics layer. It consists of two -separate sub-parts. The graphics layer is written in C. - -<ul> - -<li>The <a href="#Graphics_library">graphics library</a> manages graphics -state information for, and decomposes and renders 2-D images described -using, a graphics model that is approximately the union of those of -PostScript, PDF, and PCL 5e/5c/XL. - -<li>The <a href="#Device_drivers">device drivers</a> are called by the -graphics library to produce actual output. The graphics library, and all -higher layers, call device driver procedures only through virtual functions. - -</ul> - -<li>The principal clients of the graphics layer are language interpreters. -Ghostscript as distributed includes the <a -href="#PostScript_interpreter">PostScript interpreter</a>; there are also -interpreters for PCL 5e, PCL 5c, and PCL XL, which are not currently freely -redistributable and are not included in the standard Ghostscript package. -The PostScript interpreter is written partly in C and partly in PostScript. - -<li>The <a href="#PDF_interpreter">PDF interpreter</a> is actually a client -of the PostScript interpreter: it is written entirely in PostScript. - -</ol> - -<p> -The most important interface in Ghostscript is the API between the graphics -library and the device drivers: new printers (and, to a lesser extent, -window systems, displays, plotters, film recorders, and graphics file -formats) come on the scene frequently, and it must be possible to produce -output for them with a minimum of effort and distruption. This API is the -only one that is extensively documented (see <a -href="Drivers.htm">Drivers.htm</a>) and kept stringently backward-compatible -through successive releases. - -<h3><a name="Object_oriented_constructs"></a>Object-oriented constructs</h3> - -<p> -Ghostscript makes heavy use of object-oriented constructs, including -analogues of classes, instances, subclassing, and class-associated -procedures. Since Ghostscript is written in C, not C++, implementing these -constructs requires following coding conventions. The <a -href="C-style.htm#Objects">"Objects"</a> section of the C style guide -explains these. - -<p> -The memory manager API provides run-time type information about each class, -but this information does not include anything about subclassing. See under -<a href="#Structure_descriptors">Structure descriptors</a> below. - -<hr> - -<h2><a name="File_roadmap"></a>File roadmap</h2> - -<p> -This section of the document provides a roadmap to all of the Ghostscript -source files. - -<h3><a name="Substrate"></a>Substrate</h3> - -<h4>Runtime Context</h4> - -<dl> -<dt> -The libctx provides pointers to memory, stdio, and various other runtime -portablility services. -<dd> -<a href="../base/gslibctx.h">base/gslibctx.h</a>, -<a href="../base/gslibctx.c">base/gslibctx.c</a>. -</dl> - -<h4>Memory manager</h4> - -<p> -See <a href="#Memory_management">below</a>. - -<h4>Streams</h4> - -<dl> - -<dt> -Framework, file and string streams: -<dd> -<a href="../base/gsdsrc.c">base/gsdsrc.c</a>, -<a href="../base/gsdsrc.h">base/gsdsrc.h</a>, -<a href="../base/scommon.h">base/scommon.h</a>, -<a href="../base/strmio.c">base/strmio.c</a>, -<a href="../base/strmio.h">base/strmio.h</a>, -<a href="../base/sfxboth.c">base/sfxboth.c</a>, -<a href="../base/sfxfd.c">base/sfxfd.c</a>, -<a href="../base/sfxstdio.c">base/sfxstdio.c</a>, -<a href="../base/sfxcommon.c">base/sfxcommon.c</a>, -<a href="../base/stream.h">base/stream.h</a>, -<a href="../base/stream.c">base/stream.c</a>, -<a href="../base/strimpl.h">base/strimpl.h</a>. - -<dt> -Standard filters: -<dd> - -<dl> - -<dt> -CCITTFax: -<dd> -<a href="../base/scf.h">base/scf.h</a>, -<a href="../base/scfd.c">base/scfd.c</a>, -<a href="../base/scfdgen.c">base/scfdgen.c</a>, -<a href="../base/scfdtab.c">base/scfdtab.c</a>, -<a href="../base/scfe.c">base/scfe.c</a>, -<a href="../base/scfetab.c">base/scfetab.c</a>, -<a href="../base/scfparam.c">base/scfparam.c</a>, -<a href="../base/scfx.h">base/scfx.h</a>. - -<dt> -DCT (JPEG): -<dd> -<a href="../base/gsjconf.h">base/gsjconf.h</a>, -<a href="../base/gsjmorec.h">base/gsjmorec.h</a>, -<a href="../base/sdcparam.c">base/sdcparam.c</a>, -<a href="../base/sdcparam.h">base/sdcparam.h</a>, -<a href="../base/sdct.h">base/sdct.h</a>, -<a href="../base/sdctc.c">base/sdctc.c</a>, -<a href="../base/sdctd.c">base/sdctd.c</a>, -<a href="../base/sdcte.c">base/sdcte.c</a>, -<a href="../base/sddparam.c">base/sddparam.c</a>, -<a href="../base/sdeparam.c">base/sdeparam.c</a>, -<a href="../base/sjpeg.h">base/sjpeg.h</a>, -<a href="../base/sjpegc.c">base/sjpegc.c</a>, -<a href="../base/sjpegd.c">base/sjpegd.c</a>, -<a href="../base/sjpege.c">base/sjpege.c</a>. - -<dt> -JBIG2: -<a href="../base/sjbig2.h">base/sjbig2.h</a>, -<a href="../base/sjbig2.c">base/sjbig2.c</a> -<dt> -JPX (JPEG 2000): -<a href="../base/sjpx_openjpeg.h">base/sjpx_openjpeg.h</a>, -<a href="../base/sjpx_openjpeg.c">base/sjpx_openjpeg.c</a> -<dt> -Other compression/decompression: -<dd> -<a href="../base/slzwc.c">base/slzwc.c</a>, -<a href="../base/slzwd.c">base/slzwd.c</a>, -<a href="../base/slzwe.c">base/slzwe.c</a>, -<a href="../base/slzwx.h">base/slzwx.h</a>, -<a href="../base/srld.c">base/srld.c</a>, -<a href="../base/srle.c">base/srle.c</a>, -<a href="../base/srlx.h">base/srlx.h</a>. - -<dt> -Other: -<dd> -<a href="../base/sa85d.c">base/sa85d.c</a>, -<a href="../base/sa85d.h">base/sa85d.h</a>, -<a href="../base/sa85x.h">base/sa85x.h</a>, -<a href="../psi/sfilter1.c">psi/sfilter1.c</a>, -<a href="../base/sfilter2.c">base/sfilter2.c</a>, -<a href="../base/sstring.c">base/sstring.c</a>, -<a href="../base/sstring.h">base/sstring.h</a>. - -</dl> - -<dt> -Non-standard filters used to implement standard filters: -<dd> -<a href="../base/seexec.c">base/seexec.c</a>, -<a href="../base/sfilter.h">base/sfilter.h</a>, -<a href="../base/shc.c">base/shc.c</a>, -<a href="../base/shc.h">base/shc.h</a>, -<a href="../base/spdiff.c">base/spdiff.c</a>, -<a href="../base/spdiffx.h">base/spdiffx.h</a>, -<a href="../base/spngp.c">base/spngp.c</a>, -<a href="../base/spngpx.h">base/spngpx.h</a>, -<a href="../base/szlibc.c">base/szlibc.c</a>, -<a href="../base/szlibd.c">base/szlibd.c</a>, -<a href="../base/szlibe.c">base/szlibe.c</a>, -<a href="../base/szlibx.h">base/szlibx.h</a>, -<a href="../base/szlibxx.h">base/szlibxx.h</a>. - -<dt> -Non-standard filters: -<dd> -<a href="../base/sbcp.c">base/sbcp.c</a>, -<a href="../base/sbcp.h">base/sbcp.h</a>, -<a href="../base/sbtx.h">base/sbtx.h</a>, -<a href="../base/smd5.c">base/smd5.c</a>, -<a href="../base/smd5.h">base/smd5.h</a>, -<a href="../base/saes.c">base/saes.c</a>, -<a href="../base/saes.h">base/saes.h</a>, -<a href="../base/sarc4.c">base/sarc4.c</a>, -<a href="../base/sarc4.h">base/sarc4.h</a>, - -<dt> -Internal filters: -<dd> -<a href="../base/siinterp.c">base/siinterp.c</a>, -<a href="../base/siinterp.h">base/siinterp.h</a>, -<a href="../base/siscale.c">base/siscale.c</a>, -<a href="../base/siscale.h">base/siscale.h</a>, -<a href="../base/sidscale.c">base/sidscale.c</a>, -<a href="../base/sidscale.h">base/sidscale.h</a>, -<a href="../base/sisparam.h">base/sisparam.h</a>. - -<dt> -Higher-level stream support: -<dd> -<a href="../base/spprint.c">base/spprint.c</a>, -<a href="../base/spprint.h">base/spprint.h</a>, -<a href="../base/spsdf.c">base/spsdf.c</a>, -<a href="../base/spsdf.h">base/spsdf.h</a>, -<a href="../base/srdline.h">base/srdline.h</a>. - -</dl> - -<h4>Platform-specific code</h4> - -See <a href="#Cross_platform_APIs">below</a>. - -<h4>Miscellaneous</h4> - -<dl> - -<dt> -Library top level: -<dd> -<a href="../base/gsinit.c">base/gsinit.c</a>, -<a href="../base/gslib.h">base/gslib.h</a>. - -<dt> -Configuration-related: -<dd> -<a href="../base/gconf.c">base/gconf.c</a>, -<a href="../base/gconf.h">base/gconf.h</a>, -<a href="../base/gscdef.c">base/gscdef.c</a>, -<a href="../base/gscdefs.h">base/gscdefs.h</a>, -<a href="../base/gsromfs0.c">base/gsromfs0.c</a>. - -<dt> -Arithmetic: -<dd> -<a href="../base/gxarith.h">base/gxarith.h</a>, -<a href="../base/gxdda.h">base/gxdda.h</a>, -<a href="../base/gxfarith.h">base/gxfarith.h</a>, -<a href="../base/gxfixed.h">base/gxfixed.h</a>, -<a href="../base/gxfrac.h">base/gxfrac.h</a>. - -<dt> -Operating system interface: -<dd> -<a href="../base/gserrors.h">base/gserrors.h</a>, -<a href="../base/gsexit.h">base/gsexit.h</a>, -<a href="../base/gxstdio.h">base/gxstdio.h</a>, -<a href="../base/gxsync.c">base/gxsync.c</a>, -<a href="../base/gxsync.h">base/gxsync.h</a>. - -<dt> -Other: -<dd> -<a href="../base/gsargs.c">base/gsargs.c</a>, -<a href="../base/gsargs.h">base/gsargs.h</a>, -<a href="../base/gserrors.h">base/gserrors.h</a>, -<a href="../base/gsnotify.c">base/gsnotify.c</a>, -<a href="../base/gsnotify.h">base/gsnotify.h</a>, -<a href="../base/gsrect.h">base/gsrect.h</a>, -<a href="../base/gstypes.h">base/gstypes.h</a>, -<a href="../base/gsuid.h">base/gsuid.h</a>, -<a href="../base/gsutil.h">base/gsutil.h</a>, -<a href="../base/gsutil.c">base/gsutil.c</a>, -<a href="../base/gx.h">base/gx.h</a>, -<a href="../base/gsmd5.c">base/gsmd5.c</a>, -<a href="../base/gsmd5.h">base/gsmd5.h</a>, -<a href="../base/aes.c">base/aes.c</a>, -<a href="../base/aes.h">base/aes.h</a>. - -</dl> - -<h3><a name="Graphics_library"></a>Graphics library</h3> - -<h4><a name="Library_support"></a>Support</h4> - -<dl> - -<dt> -Bitmap processing: -<dd> -<a href="../base/gsbitcom.c">base/gsbitcom.c</a>, -<a href="../base/gsbitmap.h">base/gsbitmap.h</a>, -<a href="../base/gsbitops.c">base/gsbitops.c</a>, -<a href="../base/gsbitops.h">base/gsbitops.h</a>, -<a href="../base/gsbittab.c">base/gsbittab.c</a>, -<a href="../base/gsbittab.h">base/gsbittab.h</a>, -<a href="../base/gsflip.c">base/gsflip.c</a>, -<a href="../base/gsflip.h">base/gsflip.h</a>, -<a href="../base/gxbitmap.h">base/gxbitmap.h</a>, -<a href="../base/gxbitops.h">base/gxbitops.h</a>, -<a href="../base/gxsample.c">base/gxsample.c</a>, -<a href="../base/gxsample.h">base/gxsample.h</a>. -<a href="../base/gxsamplp.h">base/gxsamplp.h</a>. - -<dt> -Functions: -<dd> -<a href="../base/gsfunc.c">base/gsfunc.c</a>, -<a href="../base/gsfunc.h">base/gsfunc.h</a>, -<a href="../base/gsfunc0.c">base/gsfunc0.c</a>, -<a href="../base/gsfunc0.h">base/gsfunc0.h</a>, -<a href="../base/gsfunc3.c">base/gsfunc3.c</a>, -<a href="../base/gsfunc3.h">base/gsfunc3.h</a>, -<a href="../base/gsfunc4.c">base/gsfunc4.c</a>, -<a href="../base/gsfunc4.h">base/gsfunc4.h</a>, -<a href="../base/gxfunc.h">base/gxfunc.h</a>. - -<dt> -Parameter lists: -<dd> -<a href="../base/gscparam.c">base/gscparam.c</a>, -<a href="../base/gsparam.c">base/gsparam.c</a>, -<a href="../base/gsparam.h">base/gsparam.h</a>, -<a href="../base/gsparam2.c">base/gsparam2.c</a> (not used), -<a href="../base/gsparams.c">base/gsparams.c</a>, -<a href="../base/gsparams.h">base/gsparams.h</a>, -<a href="../base/gsparamx.c">base/gsparamx.c</a>, -<a href="../base/gsparamx.h">base/gsparamx.h</a>. - -<dt> -I/O-related: -<dd> -<a href="../base/gdevpipe.c">base/gdevpipe.c</a>, -<a href="../base/gsfname.c">base/gsfname.c</a>, -<a href="../base/gsfname.h">base/gsfname.h</a>, -<a href="../base/gsio.h">base/gsio.h</a>, -<a href="../base/gsiodev.c">base/gsiodev.c</a>, -<a href="../base/gsiodevs.c">base/gsiodevs.c</a>, -<a href="../base/gsiodisk.c">base/gsiodisk.c</a>, -<a href="../base/gsiorom.c">base/gsiorom.c</a>. -<a href="../base/gsiorom.h">base/gsiorom.h</a>. -<a href="../base/gxiodev.h">base/gxiodev.h</a>. - -</dl> - -<h4><a name="Paths"></a>Paths</h4> - -<dl> - -<dt> -Coordinate transformation: -<dd> -<a href="../base/gscoord.c">base/gscoord.c</a>, -<a href="../base/gscoord.h">base/gscoord.h</a>, -<a href="../base/gsmatrix.c">base/gsmatrix.c</a>, -<a href="../base/gsmatrix.h">base/gsmatrix.h</a>, -<a href="../base/gxcoord.h">base/gxcoord.h</a>, -<a href="../base/gxmatrix.h">base/gxmatrix.h</a>. - -<dt> -Path building: -<dd> -<a href="../base/gsdps1.c">base/gsdps1.c</a>, -<a href="../base/gspath.c">base/gspath.c</a>, -<a href="../base/gspath.h">base/gspath.h</a>, -<a href="../base/gspath1.c">base/gspath1.c</a>, -<a href="../base/gspath2.h">base/gspath2.h</a>, -<a href="../base/gxpath.c">base/gxpath.c</a>, -<a href="../base/gxpath.h">base/gxpath.h</a>, -<a href="../base/gxpath2.c">base/gxpath2.c</a>, -<a href="../base/gxpcopy.c">base/gxpcopy.c</a>, -<a href="../base/gxpdash.c">base/gxpdash.c</a>, -<a href="../base/gxpflat.c">base/gxpflat.c</a>, -<a href="../base/gzpath.h">base/gzpath.h</a>. - -<dt> -Path rendering: -<dd> -<a href="../base/gdevddrw.c">base/gdevddrw.c</a>, -<a href="../base/gdevddrw.h">base/gdevddrw.h</a>, -<a href="../base/gxdtfill.h">base/gxdtfill.h</a>, -<a href="../base/gsdps1.c">base/gsdps1.c</a>, -<a href="../base/gspaint.c">base/gspaint.c</a>, -<a href="../base/gspaint.h">base/gspaint.h</a>, -<a href="../base/gspenum.h">base/gspenum.h</a>, -<a href="../base/gxfill.c">base/gxfill.c</a>, -<a href="../base/gxfill.h">base/gxfill.h</a>, -<a href="../base/gxfillsl.h">base/gxfillsl.h</a>, -<a href="../base/gxfilltr.h">base/gxfilltr.h</a>, -<a href="../base/gxfillts.h">base/gxfillts.h</a>, -<a href="../base/gximask.c">base/gximask.c</a>, -<a href="../base/gximask.h">base/gximask.h</a>, -<a href="../base/gxfdrop.c">base/gxfdrop.c</a>, -<a href="../base/gxfdrop.h">base/gxfdrop.h</a>, -<a href="../base/gxpaint.c">base/gxpaint.c</a>, -<a href="../base/gxpaint.h">base/gxpaint.h</a>, -<a href="../base/gxstroke.c">base/gxstroke.c</a>, -<a href="../base/gzspotan.c">base/gzspotan.c</a>, -<a href="../base/gzspotan.h">base/gzspotan.h</a>. - -<dt> -Clipping: -<dd> -See under <a href="#Clipping">Clipping</a> below. - -</dl> - -<h4><a name="Text"></a>Text</h4> - -<dl> - -<dt> -Fonts, generic: -<dd> -<a href="../base/gsfont.c">base/gsfont.c</a>, -<a href="../base/gsfont.h">base/gsfont.h</a>, -<a href="../devices/gxfcopy.c">devices/gxfcopy.c</a>, -<a href="../devices/gxfcopy.h">devices/gxfcopy.h</a>, -<a href="../base/gxfont.h">base/gxfont.h</a>. - -<dt> -Fonts, specific FontTypes: -<dd> -<a href="../base/gsfcid.c">base/gsfcid.c</a>, -<a href="../base/gsfcid2.c">base/gsfcid.c</a>, -<a href="../base/gsfcmap.c">base/gsfcmap.c</a>, -<a href="../base/gsfcmap1.c">base/gsfcmap1.c</a>, -<a href="../base/gsfcmap.h">base/gsfcmap.h</a>, -<a href="../base/gsfont0.c">base/gsfont0.c</a>, -<a href="../base/gsfont0c.c">base/gsfont0c.c</a>, -<a href="../base/gxcid.h">base/gxcid.h</a>, -<a href="../base/gxfcid.h">base/gxfcid.h</a>, -<a href="../base/gxfcmap.h">base/gxfcmap.h</a>, -<a href="../base/gxfcmap1.h">base/gxfcmap1.h</a>, -<a href="../base/gxfont0.h">base/gxfont0.h</a>, -<a href="../base/gxfont0c.h">base/gxfont0c.h</a>, -<a href="../base/gxfont1.h">base/gxfont1.h</a>, -<a href="../base/gxfont42.h">base/gxfont42.h</a>, -<a href="../base/gxftype.h">base/gxftype.h</a>, -<a href="../base/gxttf.h">base/gxttf.h</a>. - -<dt> -Character rendering + font cache, generic: -<dd> -<a href="../base/gsccode.h">base/gsccode.h</a>, -<a href="../base/gschar.c">base/gschar.c</a>, -<a href="../base/gschar.h">base/gschar.h</a>, -<a href="../base/gscpm.h">base/gscpm.h</a>, -<a href="../base/gsgdata.c">base/gsgdata.c</a>, -<a href="../base/gsgdata.h">base/gsgdata.h</a>, -<a href="../base/gsgcache.c">base/gsgcache.c</a>, -<a href="../base/gsgcache.h">base/gsgcache.h</a>, -<a href="../base/gstext.c">base/gstext.c</a>, -<a href="../base/gstext.h">base/gstext.h</a>, -<a href="../base/gxbcache.c">base/gxbcache.c</a>, -<a href="../base/gxbcache.h">base/gxbcache.h</a>, -<a href="../base/gxccache.c">base/gxccache.c</a>, -<a href="../base/gxccman.c">base/gxccman.c</a>, -<a href="../base/gxchar.c">base/gxchar.c</a>, -<a href="../base/gxchar.h">base/gxchar.h</a>, -<a href="../base/gxfcache.h">base/gxfcache.h</a>, -<a href="../base/gxtext.h">base/gxtext.h</a>. - -<dt> -Character rendering, specific FontTypes: -<dd> -<a href="../base/gschar0.c">base/gschar0.c</a>, -<a href="../base/gscrypt1.c">base/gscrypt1.c</a>, -<a href="../base/gscrypt1.h">base/gscrypt1.h</a>, -<a href="../base/gstype1.c">base/gstype1.c</a>, -<a href="../base/gstype1.h">base/gstype1.h</a>, -<a href="../base/gstype2.c">base/gstype2.c</a>, -<a href="../base/gstype42.c">base/gstype42.c</a>, -<a href="../base/gxchrout.c">base/gxchrout.c</a>, -<a href="../base/gxchrout.h">base/gxchrout.h</a>, -<a href="../base/gxhintn.h">base/gxhintn.h</a>, -<a href="../base/gxhintn.c">base/gxhintn.c</a>, -<a href="../base/gxhintn1.c">base/gxhintn1.c</a>, -<a href="../base/gxtype1.c">base/gxtype1.c</a>, -<a href="../base/gxtype1.h">base/gxtype1.h</a>. - -</dl> - -<h4><a name="Images"></a>Images</h4> - -<dl> - -<dt> -Buffered API (mostly for PostScript interpreter): -<dd> -<a href="../base/gsimage.c">base/gsimage.c</a>, -<a href="../base/gsimage.h">base/gsimage.h</a>. - -<dt> -Generic support: -<dd> -<a href="../base/gsiparam.h">base/gsiparam.h</a>, -<a href="../base/gxiclass.h">base/gxiclass.h</a>, -<a href="../base/gximage.c">base/gximage.c</a>, -<a href="../base/gximage.h">base/gximage.h</a>, -<a href="../base/gxiparam.h">base/gxiparam.h</a>. - -<dt> -Type 1 and 4 images: -<dd> - -<dl> - -<dt> -Setup: -<dd> -<a href="../base/gsiparm4.h">base/gsiparm4.h</a>, -<a href="../base/gximage1.c">base/gximage1.c</a>, -<a href="../base/gximage4.c">base/gximage4.c</a>. - -<dt> -Rendering: -<dd> -<a href="../base/gxi12bit.c">base/gxi12bit.c</a>, -<a href="../base/gxi16bit.c">base/gxi16bit.c</a>, -<a href="../base/gxicolor.c">base/gxicolor.c</a>, -<a href="../base/gxidata.c">base/gxidata.c</a>, -<a href="../base/gxifast.c">base/gxifast.c</a>, -<a href="../base/gximono.c">base/gximono.c</a>, -<a href="../base/gxino12b.c">base/gxino12b.c</a>, -<a href="../base/gxino16b.c">base/gxino16b.c</a>, -<a href="../base/gxipixel.c">base/gxipixel.c</a>, -<a href="../base/gxiscale.c">base/gxiscale.c</a>. - -</dl> - -<dt> -Type 2 images (Display PostScript): -<dd> -<a href="../base/gsiparm2.h">base/gsiparm2.h</a>, -<a href="../base/gximage2.c">base/gximage2.c</a>. - -<dt> -Type 3 images: -<dd> -<a href="../base/gsipar3x.h">base/gsipar3x.h</a>, -<a href="../base/gsiparm3.h">base/gsiparm3.h</a>, -<a href="../base/gximag3x.c">base/gximag3x.c</a>, -<a href="../base/gximag3x.h">base/gximag3x.h</a>, -<a href="../base/gximage3.c">base/gximage3.c</a>, -<a href="../base/gximage3.h">base/gximage3.h</a>. - -<dt> -Other: -<dd> -<a href="../base/gsimpath.c">base/gsimpath.c</a>, -<a href="../base/simscale.c">base/simscale.c</a>, -<a href="../base/simscale.h">base/simscale.h</a>. -. - -</dl> - -<h4><a name="Paint"></a>Paint</h4> - -<p> -Ghostscript uses 4 internal representations of color. We list them here in -the order in which they occur in the rendering pipeline. - -<ol> - -<li>Clients of the graphics library normally specify colors using the -<em>client color</em> structure (<code>gs_client_color</code>, defined in -<a href="../psi/gs.color.h">psi/gs.color.h</a>), consisting of one or more -numeric values and/or a pointer to a Pattern instance. This corresponds -directly to the values that would be passed to the PostScript -<code>setcolor</code> operator: one or more (floating-point) numeric -components and/or a Pattern. Client colors are interpreted relative to a -color space (<code>gs_color_space</code>, defined in <a -href="../base/gscspace.h">base/gscspace.h</a> and <a -href="../base/gxcspace.h">base/gxcspace.h</a>, with specific color spaces -defined in other files). Client colors do not explicitly reference the -color space in which they are are interpreted: <code>setcolor</code> uses -the color space in the graphics state, while images and shadings explicitly -specify the color space to be used. - -<li>For ordinary non-Pattern colors, the first step in color rendering -reduces a client color to a <em>concrete</em> color -- a set of values in a -color space that corresponds to the device's color model (except for -possible conversions between DeviceGray, DeviceRGB, and DeviceCMYK), -together with an identification of the associated color space. (The -confusion here between color spaces and color models will have to be cleaned -up when we implement native Separation/DeviceN colors.) Concrete colors are -like the numeric values in a client color, except that they are represented -by arrays of <code>frac</code> values (defined in <a -href="../base/gxfrac.h">base/gxfrac.h</a>) rather than floats. The procedure -for this step is the virtual <code>concretize_color</code> and -<code>concrete_space</code> procedures in the (original) color space. -This step reduces Indexed colors, CIEBased colors, and Separation and -DeviceN colors that use the alternate space. - -<li>The final step requires mapping a concrete color to the device's color -model, done by procedures in <a href="../base/gxcmap.c">base/gxcmap.c</a>. -These procedures combine the following three conceptual sub-steps: - -<ul> - -<li>A possible mapping between Device color spaces, possibly involving black -generation and undercolor removal. The non-trivial cases are implemented in -<a href="../base/gxdcconv.c">base/gxdcconv.c</a>. - -<li>Application of the transfer function(s) (done in-line). - -<li>Halftoning if necessary: see below. - -</ul> - -The result is called (inappropriately) a <em>device color</em> -(<code>gx_device_color</code>, defined in <a -href="../psi/gs.color.h">psi/gs.color.h</a> and <a -href="../base/gxdcolor.h">base/gxdcolor.h</a>). For ordinary non-Pattern -colors, a device color is either a pure color, or a halftone. The device -and color model associated with a device color are implicit. The procedure -for this step is the virtual <code>remap_concrete_color</code> procedure -in the color space. - -<li>The pure colors that underlie a device color are opaque <em>pixel -values</em> defined by the device (misnamed <code>gx_color_index</code>, -defined in <a href="../base/gscindex.h">base/gscindex.h</a>). The device with -which they are associated is implicit. Although the format and -interpretation of a pixel value are known only to the device, the device's -color model and color representation capabilities are public, defined by a -<code>gx_color_info</code> structure stored in the device (defined in <a -href="../base/gxdevcli.h">base/gxdevcli.h</a>). Virtual procedures of the -device driver map between pixel values and RGB or CMYK. (This area is -untidy and will need to be cleaned up when we implement native -Separation/DeviceN colors.) - -</ol> - -<p> -Steps 2 and 3 are normally combined into a single step for efficiency, as -the <code>remap_color</code> virtual procedure in a color space. - -<p> -Using a device color to actually paint pixels requires a further step called -<em>color loading</em>, implemented by the <code>load</code> virtual -procedure in the device color. This does nothing for pure colors, but loads -the caches for halftones and Patterns. - -<p> -All of the above steps -- concretizing, mapping to a device color, and color -loading -- are done as late as possible, normally not until the color is -actually needed for painting. - -<p> -All painting operations (fill, stroke, imagemask/show) eventually call a -virtual procedure in the device color, either <code>fill_rectangle</code> -or <code>fill_mask</code> to actually paint pixels. For rectangle fills, -pure colors call the device's <code>fill_rectangle</code> procedure; -halftones and tiled Patterns call the device's -<code>strip_tile_rectangle</code>; shaded Patterns, and painting operations -that involve a RasterOp, do something more complicated. - -<dl> - -<dt> -Color specification: -<dd> -<a href="../base/gsdcolor.h">base/gsdcolor.h</a>, -<a href="../base/gscolor.c">base/gscolor.c</a>, -<a href="../base/gscolor.h">base/gscolor.h</a>, -<a href="../base/gscolor1.c">base/gscolor1.c</a>, -<a href="../base/gscolor1.h">base/gscolor1.h</a>, -<a href="../base/gscolor2.c">base/gscolor2.c</a>, -<a href="../base/gscolor2.h">base/gscolor2.h</a>, -<a href="../base/gscolor3.c">base/gscolor3.c</a>, -<a href="../base/gscolor3.h">base/gscolor3.h</a>, -<a href="../base/gshsb.c">base/gshsb.c</a>, -<a href="../base/gshsb.h">base/gshsb.h</a>, -<a href="../base/gxcolor2.h">base/gxcolor2.h</a>, -<a href="../base/gxcvalue.h">base/gxcvalue.h</a>. - -<dt> -Color spaces: -<dd> -<a href="../base/gscdevn.c">base/gscdevn.c</a>, -<a href="../base/gscdevn.h">base/gscdevn.h</a>, -<a href="../base/gscie.c">base/gscie.c</a>, -<a href="../base/gscie.h">base/gscie.h</a>, -<a href="../base/gscpixel.c">base/gscpixel.c</a>, -<a href="../base/gscpixel.h">base/gscpixel.h</a>, -<a href="../base/gscscie.c">base/gscscie.c</a>, -<a href="../base/gscsepr.c">base/gscsepr.c</a>, -<a href="../base/gscsepr.h">base/gscsepr.h</a>, -<a href="../base/gscspace.c">base/gscspace.c</a>, -<a href="../base/gscspace.h">base/gscspace.h</a>, -<a href="../base/gscssub.c">base/gscssub.c</a>, -<a href="../base/gscssub.h">base/gscssub.h</a>, -<a href="../base/gxcdevn.h">base/gxcdevn.h</a>, -<a href="../base/gxcie.h">base/gxcie.h</a>, -<a href="../base/gxcspace.h">base/gxcspace.h</a>. - -<dt> -Color mapping: -<dd> -<a href="../base/gsciemap.c">base/gsciemap.c</a>, -<a href="../base/gscindex.h">base/gscindex.h</a>, -<a href="../base/gscrd.c">base/gscrd.c</a>, -<a href="../base/gscrd.h">base/gscrd.h</a>, -<a href="../base/gscrdp.c">base/gscrdp.c</a>, -<a href="../base/gscrdp.h">base/gscrdp.h</a>, -<a href="../base/gscsel.h">base/gscsel.h</a>, -<a href="../base/gxcindex.h">base/gxcindex.h</a>, -<a href="../base/gxcmap.c">base/gxcmap.c</a>, -<a href="../base/gxcmap.h">base/gxcmap.h</a>, -<a href="../base/gxctable.c">base/gxctable.c</a>, -<a href="../base/gxctable.h">base/gxctable.h</a>, -<a href="../base/gxdcconv.c">base/gxdcconv.c</a>, -<a href="../base/gxdcconv.h">base/gxdcconv.h</a>, -<a href="../base/gxdcolor.c">base/gxdcolor.c</a>, -<a href="../base/gxdcolor.h">base/gxdcolor.h</a>, -<a href="../base/gxdevndi.c">base/gxdevndi.c</a>, -<a href="../base/gxdevndi.h">base/gxdevndi.h</a>, -<a href="../base/gxdither.h">base/gxdither.h</a>, -<a href="../base/gxfmap.h">base/gxfmap.h</a>, -<a href="../base/gxlum.h">base/gxlum.h</a>, -<a href="../base/gxtmap.h">base/gxtmap.h</a>. - -<p> -ICC profiles are in some ways a special case of color mapping, but are -not standard in PostScript. - -<dt> -<dd> -<a href="../base/gsicc.c">base/gsicc.c</a>, -<a href="../base/gsicc.h">base/gsicc.h</a>, - -<p> -The following files provide a callback mechanism to allow a client program -to specify a special case alternate tint transforms for Separation and DeviceN -color spaces. Among other uses this can be used to provide special handling for -PANTONE colors. -<dt> -<dd> -<a href="../base/gsnamecl.c">base/gsnamecl.c</a>, -<a href="../base/gsnamecl.h">base/gsnamecl.h</a>, -<a href="../base/gsncdummy.c">base/gsncdummy.c</a>, -<a href="../base/gsncdummy.h">base/gsncdummy.h</a>, -<a href="../psi/zncdummy.c">psi/zncdummy.c</a>, - -</dl> - -<p> -Ghostscript represents halftones internally by "whitening orders" -- -essentially, arrays of arrays of bit coordinates within a halftone cell, -specifying which bits are inverted to get from halftone level K to level -K+1. The code does support all of the PostScript halftone types, but they -are all ultimately reduced to whitening orders. - -<p> -Threshold arrays, the more conventional representation of halftones, can be -mapped to whitening orders straightforwardly; however, whitening orders can -represent non-monotonic halftones (halftones where the bits turned on for -level K+1 don't necessarily include all the bits turned on for level K), -while threshold arrays cannot. On the other hand, threshold arrays allow -rapid conversion of images (using a threshold comparison for each pixel) -with no additional space, while whitening orders do not: they require -storing the rendered halftone cell for each possible level as a bitmap. - -<p> -Ghostscript uses two distinct types of rendered halftones -- that is, the -bitmap(s) that represent a particular level. - -<ul> - -<li>Binary halftones. The rendered halftone is a single bit plane; each bit -selects one of two pure colors. These are fast but limited: they are used -for monochrome output devices, or for color devices in those cases where -only two distinct colors are involved in a halftone (e.g., a pure cyan shade -on a CMYK device). The device color for a binary halftone stores a pointer -to the halftone bitmap, and the two pure colors. - -<li>Multi-plane halftones. Internally, each plane is rendered individually. -Since there isn't enough room to store all 2^N pure colors, multi-plane -halftones only store the scaled values for the individual components; the -halftone renderer maps these to the pure colors on the fly, then combines -the planes to assemble an N-bit index into the list of colors for each -pixel, and stores the color into the fully rendered halftone. - -</ul> - -<p> -The halftone level for rendering a color is computed in <a -href="../base/gxdevndi.c">base/gxdevndi.c</a>; the actual halftone mask or -tile is computed either in <a href="../base/gxcht.c">base/gxcht.c</a> (for -multi-plane halftones), or in <a href="../base/gxht.c">base/gxht.c</a> and <a -href="../base/gxhtbit.c">base/gxhtbit.c</a> (for binary halftones). - -<dl> - -<dt> -Halftoning: -<dd> -<a href="../base/gsht.c">base/gsht.c</a>, -<a href="../base/gsht.h">base/gsht.h</a>, -<a href="../base/gsht1.c">base/gsht1.c</a>, -<a href="../base/gsht1.h">base/gsht1.h</a>, -<a href="../base/gshtscr.c">base/gshtscr.c</a>, -<a href="../base/gshtx.c">base/gshtx.c</a>, -<a href="../base/gshtx.h">base/gshtx.h</a>, -<a href="../base/gxcht.c">base/gxcht.c</a>, -<a href="../base/gxdht.h">base/gxdht.h</a>, -<a href="../base/gxdhtres.h">base/gxdhtres.h</a>, -<a href="../base/gxht.c">base/gxht.c</a>, -<a href="../base/gxht.h">base/gxht.h</a>, -<a href="../base/gxhtbit.c">base/gxhtbit.c</a>, -<a href="../base/gxhttile.h">base/gxhttile.h</a>, -<a href="../base/gxhttype.h">base/gxhttype.h</a>, -<a href="../base/gzht.h">base/gzht.h</a>. - -</dl> - -<p> -Pattern colors (tiled patterns and shadings) each use a slightly different -approach from solid colors. - -<p> -The device color for a tiled (PatternType 1) pattern contains a pointer to a -pattern instance, plus (for uncolored patterns) the device color to be -masked. The pattern instance includes a procedure that actually paints the -pattern if the pattern is not in the cache. For the PostScript interpreter, -this procedure returns an <code>gs_error_RemapColor</code> exception code: this -eventually causes the interpreter to run the pattern's PaintProc, loading -the rendering into the cache, and then re-execute the original drawing -operator. - -<dl> - -<dt> -Patterns: -<dd> -<a href="../base/gspcolor.c">base/gs.color.c</a>, -<a href="../base/gspcolor.h">base/gs.color.h</a>, -<a href="../base/gsptype1.c">base/gsptype1.c</a>, -<a href="../base/gsptype1.h">base/gsptype1.h</a>, -<a href="../base/gxp1fill.c">base/gxp1fill.c</a>, -<a href="../base/gxp1impl.h">base/gxp1impl.h</a>, -<a href="../base/gxpcache.h">base/gxpcache.h</a>, -<a href="../base/gxpcmap.c">base/gxpcmap.c</a>, -<a href="../base/gxpcolor.h">base/gxpcolor.h</a>. - -</dl> - -<p> -The device color for a shading (PatternType 2) pattern also contains a -pointer to a pattern instance. Shadings are not cached: painting with a -shading runs the shading algorithm every time. - -<dl> - -<dt> -Shading: -<dd> -<a href="../base/gsptype2.c">base/gsptype2.c</a>, -<a href="../base/gsptype2.h">base/gsptype2.h</a>, -<a href="../base/gsshade.c">base/gsshade.c</a>, -<a href="../base/gsshade.h">base/gsshade.h</a>, -<a href="../base/gxshade.c">base/gxshade.c</a>, -<a href="../base/gxshade.h">base/gxshade.h</a>, -<a href="../base/gxshade1.c">base/gxshade1.c</a>, -<a href="../base/gxshade4.c">base/gxshade4.c</a>, -<a href="../base/gxshade4.h">base/gxshade4.h</a>, -<a href="../base/gxshade6.c">base/gxshade6.c</a>, -<a href="../base/gscicach.h">base/gscicach.h</a>, -<a href="../base/gscicach.c">base/gscicach.c</a>. - -</dl> - -<p> In addition to the PostScript graphics model, Ghostscript supports RasterOp, - a weak form of alpha channel, and eventually the full PDF 1.4 transparency model. - The implemention of these facilities is quite slipshod and scattered: only RasterOp - is really implemented fully. There is a general compositing architecture, but - it is hardly used at all, and in particular is not used for RasterOp. It is - used for implementation of the general support for overprint and overprint mode. -<dl> - -<dt> -Compositing architecture: -<dd> -<a href="../base/gscompt.h">base/gscompt.h</a>, -<a href="../base/gxcomp.h">base/gxcomp.h</a>. - -<dt> -RasterOp: -<dd> -<a href="../base/gdevdrop.c">base/gdevdrop.c</a>, -<a href="../base/gdevrops.c">base/gdevrops.c</a>, -<a href="../base/gsrop.c">base/gsrop.c</a>, -<a href="../base/gsrop.h">base/gsrop.h</a>, -<a href="../base/gsropt.h">base/gsropt.h</a>, -<a href="../base/gsroptab.c">base/gsroptab.c</a>, -<a href="../base/gxdevrop.h">base/gxdevrop.h</a>. - -<dt> -Alpha channel and compositing: -<dd> -<a href="../base/gsalpha.c">base/gsalpha.c</a>, -<a href="../base/gsalpha.h">base/gsalpha.h</a>, -<a href="../base/gsdpnext.h">base/gsdpnext.h</a>, -<a href="../base/gxalpha.h">base/gxalpha.h</a>. - -<dt> -Advanced transparency: -<dd> -<a href="../base/gstparam.h">base/gstparam.h</a>, -<a href="../base/gstrans.c">base/gstrans.c</a>, -<a href="../base/gstrans.h">base/gstrans.h</a>, -<a href="../base/gxblend.c">base/gxblend.c</a>, -<a href="../base/gxblend.h">base/gxblend.h</a>, -<a href="../base/gdevp14.c">base/gdevp14.c</a>, -<a href="../base/gdevp14.h">base/gdevp14.h</a>. - -<dt> -Overprint and Overprint mode: -<dd> -<a href="../base/gsovrc.c">base/gsovrc.c</a>, -<a href="../base/gsovrc.h">base/gsovrc.h</a>, -<a href="../base/gxoprect.c">base/gxoprect.c</a>, -<a href="../base/gxoprect.h">base/gxoprect.h</a>. -There is support for both overprint and overprint mode. There is a general -compositor based implementation of these features for all devices. In addition, -the memory devices implement a higher speed set of special fill routines to -improve performance for printer based devices. - -</dl> - -<h4><a name="Clipping"></a>Clipping</h4> - -<p> -The Ghostscript graphics library implements clipping by inserting a clipping -device in the device pipeline. The clipping device modifies all drawing -operations to confine them to the clipping region. - -<p> -The library supports three different kinds of clipping: - -<dl> - -<dt> -Region/path clipping -<dd> -This corresponds to the PostScript concept of a clipping path. The clipping -region is specified either by a list of rectangles (subject to the -constraints documented in <a href="../base/gxcpath.h">base/gxcpath.h</a>), or -by a path that is converted to such a list of rectangles. - -<dt> -Stationary mask clipping -<dd> -This corresponds to the mask operand of a PostScript ImageType 3 image. The -clipping region is specified by a bitmap and an (X,Y) offset in the -coordinate space. - -<dt> -Tiled mask clipping -<dd> -This corresponds to the region painted by a PostScript Pattern, for the case -where the Pattern does not completely cover its bounding box but the -combined transformation matrix has no skew or non-orthogonal rotation (i.e., -XStep and YStep map respectively to (X,0) and (0,Y) or vice versa). The -clipping region is specified by a bitmap and an (X,Y) offset in the -coordinate space, and is replicated indefinitely in both X and Y. - -</dl> - -<p> -Note that simply scan-converting a clipping path in the usual way does not -produce a succession of rectangles that can simply be stored as the list for -region-based clipping: in general, the rectangles do not satisfy the -constraint for rectangle lists specified in <a -href="../base/gxcpath.h">base/gxcpath.h</a>, since they may overlap in X, Y, -or both. A non-trivial "clipping list accumulator" device is needed to -produce a rectangle list that does satisfy the constraint. - -<dl> - -<dt> -Clipping support: -<dd> -<a href="../base/gxclip.c">base/gxclip.c</a>, -<a href="../base/gxclip.h">base/gxclip.h</a>. - -<dt> -Region/path clipping: -<dd> -<a href="../base/gxcpath.c">base/gxcpath.c</a>, -<a href="../base/gxcpath.h">base/gxcpath.h</a>, -<a href="../base/gzcpath.h">base/gzcpath.h</a>. - -<dt> -Clipping list accumulator: -<dd> -<a href="../base/gxacpath.c">base/gxacpath.c</a>, -<a href="../base/gzacpath.h">base/gzacpath.h</a>. - -<dt> -Mask clipping support: -<dd> -<a href="../base/gxmclip.c">base/gxmclip.c</a>, -<a href="../base/gxmclip.h">base/gxmclip.h</a>. - -<dt> -Stationary mask clipping: -<dd> -<a href="../base/gxclipm.c">base/gxclipm.c</a>, -<a href="../base/gxclipm.h">base/gxclipm.h</a>. - -<dt> -Tiled mask clipping: -<dd> -<a href="../base/gxclip2.c">base/gxclip2.c</a>, -<a href="../base/gxclip2.h">base/gxclip2.h</a>. - -</dl> - -<h4><a name="Other_graphics"></a>Other graphics</h4> - -<dl> - -<dt> -Miscellaneous graphics state: -<dd> -<a href="../base/gsclipsr.c">base/gsclipsr.c</a>, -<a href="../base/gsclipsr.h">base/gsclipsr.h</a>, -<a href="../base/gsdps.c">base/gsdps.c</a>, -<a href="../base/gsdps.h">base/gsdps.h</a>, -<a href="../base/gsdps1.c">base/gsdps1.c</a>, -<a href="../base/gsistate.c">base/gsistate.c</a>, -<a href="../base/gsline.c">base/gsline.c</a>, -<a href="../base/gsline.h">base/gsline.h</a>, -<a href="../base/gslparam.h">base/gslparam.h</a>, -<a href="../base/gsstate.c">base/gsstate.c</a>, -<a href="../base/gsstate.h">base/gsstate.h</a>, -<a href="../base/gstrap.c">base/gstrap.c</a>, -<a href="../base/gstrap.h">base/gstrap.h</a>, -<a href="../base/gxclipsr.h">base/gxclipsr.h</a>, -<a href="../base/gxistate.h">base/gxistate.h</a>, -<a href="../base/gxline.h">base/gxline.h</a>, -<a href="../base/gxstate.h">base/gxstate.h</a>, -<a href="../base/gzline.h">base/gzline.h</a>, -<a href="../base/gzstate.h">base/gzstate.h</a>. - -</dl> - -<h4><a name="FAPI_support_gx"></a>Font API support</h4> - -<dl> - -<dt> -UFST bridge: -<dd> -<a href="../base/gxfapiu.c">base/gxfapiu.c</a>, -<a href="../base/gxfapiu.h">base/gxfapiu.h</a>. -</dl> - - -<h4><a name="Driver_support"></a>Driver support</h4> - -<dl> - -<dt> -Generic driver support: -<dd> -<a href="../base/gdevdcrd.c">base/gdevdcrd.c</a>, -<a href="../base/gdevdcrd.h">base/gdevdcrd.h</a>, -<a href="../base/gdevdsha.c">base/gdevdsha.c</a>, -<a href="../base/gdevemap.c">base/gdevemap.c</a>, -<a href="../base/gsdevice.c">base/gsdevice.c</a>, -<a href="../base/gsdevice.h">base/gsdevice.h</a>, -<a href="../base/gsdparam.c">base/gsdparam.c</a>, -<a href="../base/gsxfont.h">base/gsxfont.h</a>, -<a href="../base/gxdevbuf.h">base/gxdevbuf.h</a>, -<a href="../base/gxdevcli.h">base/gxdevcli.h</a>, -<a href="../base/gxdevice.h">base/gxdevice.h</a>, -<a href="../base/gxrplane.h">base/gxrplane.h</a>, -<a href="../base/gxxfont.h">base/gxxfont.h</a>. - -<dt> -Accessing rendered bits: -<dd> -<a href="../base/gdevdbit.c">base/gdevdbit.c</a>, -<a href="../base/gdevdgbr.c">base/gdevdgbr.c</a>, -<a href="../base/gxbitfmt.h">base/gxbitfmt.h</a>, -<a href="../base/gxgetbit.h">base/gxgetbit.h</a>. - -<dt> -"Printer" driver support: -<dd> -<a href="../devices/gdevmeds.c">devices/gdevmeds.c</a>, -<a href="../devices/gdevmeds.h">devices/gdevmeds.h</a>, -<a href="../base/gdevppla.c">base/gdevppla.c</a>, -<a href="../base/gdevppla.h">base/gdevppla.h</a>, -<a href="../base/gdevprn.c">base/gdevprn.c</a>, -<a href="../base/gdevprn.h">base/gdevprn.h</a>, -<a href="../base/gdevprna.c">base/gdevprna.c</a>, -<a href="../base/gdevprna.h">base/gdevprna.h</a>, -<a href="../base/gxband.h">base/gxband.h</a>, -<a href="../base/gxpageq.c">base/gxpageq.c</a>, -<a href="../base/gxpageq.h">base/gxpageq.h</a>. - -<dt> -High-level device support: -<dd> -<a href="../base/gdevvec.c">base/gdevvec.c</a>, -<a href="../base/gdevvec.h">base/gdevvec.h</a>, -<a href="../base/gxhldevc.c">base/gxhldevc.c</a>, -<a href="../base/gxhldevc.h">base/gxhldevc.h</a>. - -<dt> -Banding: -<dd> -<a href="../base/gxclbits.c">base/gxclbits.c</a>, -<a href="../base/gxcldev.h">base/gxcldev.h</a>, -<a href="../base/gxclfile.c">base/gxclfile.c</a>, -<a href="../base/gxclimag.c">base/gxclimag.c</a>, -<a href="../base/gxclio.h">base/gxclio.h</a>, -<a href="../base/gxclist.c">base/gxclist.c</a>, -<a href="../base/gxclist.h">base/gxclist.h</a>, -<a href="../base/gxcllzw.c">base/gxcllzw.c</a>, -<a href="../base/gxclmem.c">base/gxclmem.c</a>, -<a href="../base/gxclmem.h">base/gxclmem.h</a>, -<a href="../base/gxclpage.c">base/gxclpage.c</a>, -<a href="../base/gxclpage.h">base/gxclpage.h</a>, -<a href="../base/gxclpath.c">base/gxclpath.c</a>, -<a href="../base/gxclpath.h">base/gxclpath.h</a>, -<a href="../base/gxclrast.c">base/gxclrast.c</a>, -<a href="../base/gxclread.c">base/gxclread.c</a>, -<a href="../base/gxclrect.c">base/gxclrect.c</a>, -<a href="../base/gxclthrd.c">base/gxclthrd.c</a>, -<a href="../base/gxclthrd.h">base/gxclthrd.h</a>, -<a href="../base/gxclutil.c">base/gxclutil.c</a>, -<a href="../base/gxclzlib.c">base/gxclzlib.c</a>, -<a href="../base/gxdhtserial.c">base/gxdhtserial.c</a>, -<a href="../base/gxdhtserial.h">base/gxdhtserial.h</a>, -<a href="../base/gsserial.c">base/gsserial.c</a>, -<a href="../base/gsserial.h">base/gsserial.h</a>. - -</dl> - -<h4><a name="Visual_trace"></a>Visual Trace</h4> - -<dl> - -<dt> -Visual Trace support : -<dd> -<a href="../base/vdtrace.h">base/vdtrace.h</a>, -<a href="../base/vdtrace.c">base/vdtrace.c</a>. -</dl> - -See <a href="Lib.htm">doc/Lib.htm</a> for extensive documentation on -Visual Trace instructions. - - -<h3><a name="Device_drivers"></a>Device drivers</h3> - -<p> -See <a href="Drivers.htm">doc/Drivers.htm</a> for extensive documentation on -the interface between the core code and drivers. - -<p> -The driver API includes high-level (path / image / text), mid-level -(polygon), and low-level (rectangle / raster) operations. Most devices -implement only the low-level operations, and let generic code break down the -high-level operations. However, some devices produce high-level output, and -therefore must implement the high-level operations. - -<h4><a name="Internal_devices"></a>Internal devices</h4> - -<p> -There are a number of "devices" that serve internal purposes. Some of these -are meant to be real rendering targets; others are intended for use in -device pipelines. The rendering targets are: - -<dl> - -<dt> -Memory devices, depth-independent: -<dd> -<a href="../base/gdevmem.c">base/gdevmem.c</a>, -<a href="../base/gdevmem.h">base/gdevmem.h</a>, -<a href="../base/gdevmpla.c">base/gdevmpla.c</a>, -<a href="../base/gdevmpla.h">base/gdevmpla.h</a>, -<a href="../base/gdevmrop.h">base/gdevmrop.h</a>, -<a href="../base/gsdevmem.c">base/gsdevmem.c</a>, -<a href="../base/gxdevmem.h">base/gxdevmem.h</a>. - -<dt> -Memory devices, specific depths: -<dd> -<a href="../base/gdevm1.c">base/gdevm1.c</a>, -<a href="../base/gdevm2.c">base/gdevm2.c</a>, -<a href="../base/gdevm4.c">base/gdevm4.c</a>, -<a href="../base/gdevm8.c">base/gdevm8.c</a>, -<a href="../base/gdevm16.c">base/gdevm16.c</a>, -<a href="../base/gdevm24.c">base/gdevm24.c</a>, -<a href="../base/gdevm32.c">base/gdevm32.c</a>, -<a href="../base/gdevm40.c">base/gdevm40.c</a>, -<a href="../base/gdevm48.c">base/gdevm48.c</a>, -<a href="../base/gdevm56.c">base/gdevm56.c</a>, -<a href="../base/gdevm64.c">base/gdevm64.c</a>, -<a href="../base/gdevmr1.c">base/gdevmr1.c</a>, -<a href="../base/gdevmr2n.c">base/gdevmr2n.c</a>, -<a href="../base/gdevmr8n.c">base/gdevmr8n.c</a>. - -<dt> -Alpha-related devices: -<dd> -<a href="../base/gdevabuf.c">base/gdevabuf.c</a>. - -<dt> -Other devices: -<dd> -<a href="../base/gdevdflt.c">base/gdevdflt.c</a>, -<a href="../base/gdevhit.c">base/gdevhit.c</a>, -<a href="../base/gdevmrun.c">base/gdevmrun.c</a>, -<a href="../base/gdevmrun.h">base/gdevmrun.h</a>, -<a href="../base/gdevplnx.c">base/gdevplnx.c</a>, -<a href="../base/gdevplnx.h">base/gdevplnx.h</a>. -</dl> - -<p> -The forwarding devices meant for use in pipelines are: - -<dl> - -<dt> -The bounding box device: -<dd> -<a href="../base/gdevbbox.h">base/gdevbbox.h</a>, -<a href="../base/gdevbbox.c">base/gdevbbox.c</a>. - -<dt> -Clipping devices: -<dd> -See under <a href="#Clipping">Clipping</a> above. - -<dt> -Other devices: -<dd> -<a href="../base/gdevnfwd.c">base/gdevnfwd.c</a>. - -</dl> - -<h4><a name="PS_and_PDF_writers"></a>PostScript and PDF writers</h4> - -<p> -Because PostScript and PDF have the same graphics model, lexical syntax, and -stack-based execution model, the drivers that produce PostScript and PDF -output share a significant amount of support code. In the future, the -PostScript output driver should be replaced with a slightly modified version -of the PDF driver, since the latter is far more sophisticated (in -particular, it has extensive facilities for image compression and for -handling text and fonts). - -<p> -The PDF code for handling text and fonts is complex and fragile. A major -rewrite in June 2002 was intended to make it more robust and somewhat easier -to understand, but also increased its size by about 40%, contrary to the -expectation that it would shrink. Currently both sets of code are in the -code base, with compatible APIs, selected by a line in <a -href="../devices/devs.mak">devices/devs.mak</a>. - -<dl> - -<dt> -Shared support: -<dd> - -<dl> - <dt> - Writing fonts:</dt> - <dd> - <a href="../devices/vector/gdevpsf.h">devices/vector/gdevpsf.h</a>, - <a href="../devices/vector/gdevpsf1.c">devices/vector/gdevpsf1.c</a>, - <a href="../devices/vector/gdevpsf2.c">devices/vector/gdevpsf2.c</a>, - <a href="../devices/vector/gdevpsfm.c">devices/vector/gdevpsfm.c</a>, - <a href="../devices/vector/gdevpsft.c">devices/vector/gdevpsft.c</a>, - <a href="../devices/vector/gdevpsfu.c">devices/vector/gdevpsfu.c</a>, - <a href="../devices/vector/gdevpsfx.c">devices/vector/gdevpsfx.c</a>, - <a href="../base/gscedata.c">base/gscedata.c</a>, - <a href="../base/gscedata.h">base/gscedata.h</a>, - <a href="../base/gscencs.c">base/gscencs.c</a>, - <a href="../base/gscencs.h">base/gscencs.h</a>. - - <dt> - Other:</dt> - <dd> - <a href="../devices/vector/gdevpsdf.h">devices/vector/gdevpsdf.h</a>, - <a href="../devices/vector/gdevpsdi.c">devices/vector/gdevpsdi.c</a>, - <a href="../devices/vector/gdevpsdp.c">devices/vector/gdevpsdp.c</a>, - <a href="../devices/vector/gdevpsds.c">devices/vector/gdevpsds.c</a>, - <a href="../devices/vector/gdevpsds.h">devices/vector/gdevpsds.h</a>, - <a href="../devices/vector/gdevpsdu.c">devices/vector/gdevpsdu.c</a>. - -</dl> - -<dl> -<dt> -Encapsulated PostScript output driver (epswrite):</dt> -<dd> -<a href="../devices/vector/gdevpsu.c">devices/vector/gdevpsu.c</a>, -<a href="../devices/vector/gdevpsu.h">devices/vector/gdevpsu.h</a>. -</dd> -</dl> - -<dl> -<dt> -PDF output driver (pdfwrite):</dt> -<dd></dd> -</dl> - -<dl> - -<dt> -Substrate:</dt> -<dd> -<a href="../devices/vector/gdevpdfo.c">devices/vector/gdevpdfo.c</a>, -<a href="../devices/vector/gdevpdfo.h">devices/vector/gdevpdfo.h</a>, -<a href="../devices/vector/gdevpdfr.c">devices/vector/gdevpdfr.c</a>, -<a href="../devices/vector/gdevpdfu.c">devices/vector/gdevpdfu.c</a>. -</dd> -</dl> - -<dl> -<dt> -Old text and fonts:</dt> -<dd> -<a href="../devices/vector/gdevpdfe.c">devices/vector/gdevpdfe.c</a>, -<a href="../devices/vector/gdevpdft.c">devices/vector/gdevpdft.c</a>. -</dd> -</dl> - - -<dl> -<dt> -New text and fonts:</dt> -<dd> -<a href="../devices/vector/gdevpdt.c">devices/vector/gdevpdt.c</a>, -<a href="../devices/vector/gdevpdt.h">devices/vector/gdevpdt.h</a>, -<a href="../devices/vector/gdevpdtb.c">devices/vector/gdevpdtb.c</a>, -<a href="../devices/vector/gdevpdtb.h">devices/vector/gdevpdtb.h</a>, -<a href="../devices/vector/gdevpdtc.c">devices/vector/gdevpdtc.c</a>, -<a href="../devices/vector/gdevpdtd.c">devices/vector/gdevpdtd.c</a>, -<a href="../devices/vector/gdevpdtd.h">devices/vector/gdevpdtd.h</a>, -<a href="../devices/vector/gdevpdte.c">devices/vector/gdevpdte.c</a>, -<a href="../devices/vector/gdevpdtf.c">devices/vector/gdevpdtf.c</a>, -<a href="../devices/vector/gdevpdtf.h">devices/vector/gdevpdtf.h</a>, -<a href="../devices/vector/gdevpdti.c">devices/vector/gdevpdti.c</a>, -<a href="../devices/vector/gdevpdti.h">devices/vector/gdevpdti.h</a>, -<a href="../devices/vector/gdevpdts.c">devices/vector/gdevpdts.c</a>, -<a href="../devices/vector/gdevpdts.h">devices/vector/gdevpdts.h</a>, -<a href="../devices/vector/gdevpdtt.c">devices/vector/gdevpdtt.c</a>, -<a href="../devices/vector/gdevpdtt.h">devices/vector/gdevpdtt.h</a>, -<a href="../devices/vector/gdevpdtv.c">devices/vector/gdevpdtv.c</a>, -<a href="../devices/vector/gdevpdtv.h">devices/vector/gdevpdtv.h</a>, -<a href="../devices/vector/gdevpdtw.c">devices/vector/gdevpdtw.c</a>, -<a href="../devices/vector/gdevpdtw.h">devices/vector/gdevpdtw.h</a>, -<a href="../devices/vector/gdevpdtx.h">devices/vector/gdevpdtx.h</a>. -<a href="../base/ConvertUTF.h">base/ConvertUTF.h</a>, -<a href="../base/ConvertUTF.c">base/ConvertUTF.c</a>, -</dd> -</dl> - -<dl> -<dt> -Graphics:</dt> -<dd> -<a href="../devices/vector/gdevpdfc.c">devices/vector/gdevpdfc.c</a>, -<a href="../devices/vector/gdevpdfc.h">devices/vector/gdevpdfc.h</a>, -<a href="../devices/vector/gdevpdfd.c">devices/vector/gdevpdfd.c</a>, -<a href="../devices/vector/gdevpdfg.c">devices/vector/gdevpdfg.c</a>, -<a href="../devices/vector/gdevpdfg.h">devices/vector/gdevpdfg.h</a>, -<a href="../devices/vector/gdevpdfk.c">devices/vector/gdevpdfk.c</a>, -<a href="../devices/vector/gdevpdft.c">devices/vector/gdevpdft.c</a>. -<a href="../devices/vector/gdevpdfv.c">devices/vector/gdevpdfv.c</a>. -</dd> -</dl> - -<dl> -<dt> -Images:</dt> -<dd> -<a href="../devices/vector/gdevpdfb.c">devices/vector/gdevpdfb.c</a>, -<a href="../devices/vector/gdevpdfi.c">devices/vector/gdevpdfi.c</a>, -<a href="../devices/vector/gdevpdfj.c">devices/vector/gdevpdfj.c</a>. -</dd> -</dl> - -<dl> -<dt> -Other:</dt> -<dd> -<a href="../devices/vector/gdevpdf.c">devices/vector/gdevpdf.c</a>, -<a href="../devices/vector/gdevpdfm.c">devices/vector/gdevpdfm.c</a>, -<a href="../devices/vector/gdevpdfp.c">devices/vector/gdevpdfp.c</a>, -<a href="../devices/vector/gdevpdfx.h">devices/vector/gdevpdfx.h</a>. -<a href="../devices/vector/gdevpdfb.h">devices/vector/gdevpdfb.h</a>. -</dd> - -</dl> - - - -<h4><a name="High_level_devices"></a>Other high-level devices</h4> - -<dl> - <dt> -PCL XL output device (pxlmono, pxlcolor):</dt> -<dd> -<a href="../devices/vector/gdevpx.c">devices/vector/gdevpx.c</a>, -<a href="../base/gdevpxat.h">base/gdevpxat.h</a>, -<a href="../base/gdevpxen.h">base/gdevpxen.h</a>, -<a href="../base/gdevpxop.h">base/gdevpxop.h</a>, -<a href="../devices/gdevpxut.c">devices/gdevpxut.c</a>, -<a href="../devices/gdevpxut.h">devices/gdevpxut.h</a>. -</dd> -</dl> - -<dl> - -<dt> -Text extraction:</dt> -<dd> -<a href="../devices/vector/gdevtxtw.c">devices/vector/gdevtxtw.c</a>. -</dd> -</dl> -<dl> -<dt> -Other high-level devices:</dt> -<dd> -<a href="../devices/gdevtrac.c">devices/gdevtrac.c</a>. -</dd> -</dl> - - -<h4><a name="Other_maintained_drivers"></a>Other maintained drivers</h4> - -<p> -The standard Ghostscript distribution includes a collection of drivers, -mostly written by Aladdin Enterprises, that are "maintained" in the same -sense as the Ghostscript core code. - -<dl> - -<dt> -Display drivers:</dt> -<dd> -<a href="../devices/gdev8bcm.c">devices/gdev8bcm.c</a>, -<a href="../devices/gdev8bcm.h">devices/gdev8bcm.h</a>, -<a href="../devices/gdevevga.c">devices/gdevevga.c</a>, -<a href="../devices/gdevl256.c">devices/gdevl256.c</a>, -<a href="../base/gdevpccm.c">base/gdevpccm.c</a>, -<a href="../base/gdevpccm.h">base/gdevpccm.h</a>, -<a href="../devices/gdevpcfb.c">devices/gdevpcfb.c</a>, -<a href="../devices/gdevpcfb.h">devices/gdevpcfb.h</a>, -<a href="../devices/gdevs3ga.c">devices/gdevs3ga.c</a>, -<a href="../devices/gdevsco.c">devices/gdevsco.c</a>, -<a href="../devices/gdevsvga.c">devices/gdevsvga.c</a>, -<a href="../devices/gdevsvga.h">devices/gdevsvga.h</a>, -<a href="../devices/gdevvglb.c">devices/gdevvglb.c</a>. -</dd> -</dl> - -<dl> -<dt> -Window system drivers:</dt> -<dd></dd> -</dl> - -<dl> - -<dt> -X Windows:</dt> -<dd> -<a href="../devices/gdevx.c">devices/gdevx.c</a>, -<a href="../devices/gdevx.h">devices/gdevx.h</a>, -<a href="../devices/gdevxalt.c">devices/gdevxalt.c</a>, -<a href="../devices/gdevxcmp.c">devices/gdevxcmp.c</a>, -<a href="../devices/gdevxcmp.h">devices/gdevxcmp.h</a>, -<a href="../devices/gdevxini.c">devices/gdevxini.c</a>, -<a href="../devices/gdevxres.c">devices/gdevxres.c</a>. -</dd> -</dl> - -<dl> -<dt> -Microsoft Windows:</dt> -<dd> -<a href="../devices/gdevmswn.c">devices/gdevmswn.c</a>, -<a href="../devices/gdevmswn.h">devices/gdevmswn.h</a>, -<a href="../devices/gdevmsxf.c">devices/gdevmsxf.c</a>, -<a href="../devices/gdevwddb.c">devices/gdevwddb.c</a>, -<a href="../devices/gdevwdib.c">devices/gdevwdib.c</a>.</dd> - -<dt> -OS/2 Presentation Manager:</dt> -<dd> -<a href="../devices/gdevpm.h">devices/gdevpm.h</a>, -<a href="../base/gspmdrv.c">base/gspmdrv.c</a>, -<a href="../base/gspmdrv.h">base/gspmdrv.h</a>.</dd> - -</dl> - -<dl> -<dt> -Raster file output drivers:</dt> -<dd></dd> -</dl> - -<dl> - -<dt> -Fax and TIFF:</dt> -<dd> -<a href="../devices/gdevfax.c">devices/gdevfax.c</a>, -<a href="../devices/gdevfax.h">devices/gdevfax.h</a>, -<a href="../devices/gdevtfax.c">devices/gdevtfax.c</a>, -<a href="../devices/gdevtfax.h">devices/gdevtfax.h</a>, -<a href="../devices/gdevtifs.c">devices/gdevtifs.c</a>, -<a href="../devices/gdevtifs.h">devices/gdevtifs.h</a>, -<a href="../devices/gdevtfnx.c">devices/gdevtfnx.c</a>. -<a href="../devices/gdevtsep.c">devices/gdevtsep.c</a>. - -</dd> - -<dt> -Example DeviceN devices: -<dd> -<a href="../base/gdevdevn.c">base/gdevdevn.c</a>, -<a href="../base/gdevdevn.h">base/gdevdevn.h</a>, -<a href="../devices/gdevxcf.c">devices/gdevxcf.c</a>, -<a href="../devices/gdevpsd.c">devices/gdevpsd.c</a>, -<a href="../devices/gdevperm.c">devices/gdevperm.c</a>. - -</dd> - -<dt> -Other raster file formats: -<dd> -<a href="../devices/gdevbit.c">devices/gdevbit.c</a>, -<a href="../devices/gdevbmp.c">devices/gdevbmp.c</a>, -<a href="../devices/gdevbmp.h">devices/gdevbmp.h</a>, -<a href="../devices/gdevbmpa.c">devices/gdevbmpa.c</a>, -<a href="../devices/gdevbmpc.c">devices/gdevbmpc.c</a>, -<a href="../devices/gdevjpeg.c">devices/gdevjpeg.c</a>, -<a href="../devices/gdevmiff.c">devices/gdevmiff.c</a>, -<a href="../devices/gdevp2up.c">devices/gdevp2up.c</a>, -<a href="../devices/gdevpcx.c">devices/gdevpcx.c</a>, -<a href="../devices/gdevpbm.c">devices/gdevpbm.c</a>, -<a href="../devices/gdevpng.c">devices/gdevpng.c</a>, -<a href="../devices/gdevpsim.c">devices/gdevpsim.c</a>. - -</dd> - -</dl> - -<dl> -<dt> -Printer drivers: -<dd> - -<dl> - -<dt> -Operating system printer services: -<dd> -<a href="../devices/gdevos2p.c">devices/gdevos2p.c</a>, -<a href="../devices/gdevwpr2.c">devices/gdevwpr2.c</a>, -<a href="../devices/gdevwprn.c">devices/gdevwprn.c</a>. - -<dt> -H-P monochrome printers: -<dd> -<a href="../devices/gdevdljm.c">devices/gdevdljm.c</a>, -<a href="../devices/gdevdljm.h">devices/gdevdljm.h</a>, -<a href="../devices/gdevdjet.c">devices/gdevdjet.c</a>, -<a href="../devices/gdevlj56.c">devices/gdevlj56.c</a>. - -<dt> -Other printers: -<dd> -<a href="../devices/gdevatx.c">devices/gdevatx.c</a>. - -</dl> - -</dl> - -<h4><a name="Contributed_drivers"></a>Contributed drivers</h4> - -<p> -This list is likely to be incomplete and inaccurate: see -<a href="../devices/contrib.mak">devices/contrib.mak</a> and -<a href="../contrib/contrib.mak">contrib/contrib.mak</a>. - -<dl> - -<dt> -Display and window system drivers: -<dd> -<a href="../devices/gdev3b1.c">devices/gdev3b1.c</a>, -<a href="../devices/gdevherc.c">devices/gdevherc.c</a>, -<a href="../devices/gdevpe.c">devices/gdevpe.c</a>, -<a href="../devices/gdevsnfb.c">devices/gdevsnfb.c</a>, -<a href="../devices/gdevsun.c">devices/gdevsun.c</a>. - -<dt> -Raster file output drivers: -<dd> -<a href="../devices/gdevcfax.c">devices/gdevcfax.c</a>, -<a href="../devices/gdevcif.c">devices/gdevcif.c</a>, -<a href="../devices/gdevdfax.c">devices/gdevdfax.c</a>, -<a href="../devices/gdevifno.c">devices/gdevifno.c</a>, -<a href="../devices/gdevmgr.c">devices/gdevmgr.c</a>, -<a href="../devices/gdevmgr.h">devices/gdevmgr.h</a>, -<a href="../devices/gdevsgi.c">devices/gdevsgi.c</a>, -<a href="../devices/gdevsgi.h">devices/gdevsgi.h</a>, -<a href="../devices/gdevsunr.c">devices/gdevsunr.c</a>, -<a href="../devices/gdevjbig2.c">devices/gdevjbig2.c</a>, -<a href="../devices/gdevjpx.c">devices/gdevjpx.c</a>. - -<dt> -Printer drivers: -<dd> -<a href="../lib/bj8.rpd">lib/bj8.rpd</a>, -<a href="../lib/cbjc600.ppd">lib/cbjc600.ppd</a>, -<a href="../lib/cbjc800.ppd">lib/cbjc800.ppd</a>, -<a href="../devices/gdev3852.c">devices/gdev3852.c</a>, -<a href="../devices/gdev4081.c">devices/gdev4081.c</a>, -<a href="../devices/gdev4693.c">devices/gdev4693.c</a>, -<a href="../devices/gdev8510.c">devices/gdev8510.c</a>, -<a href="../devices/gdevadmp.c">devices/gdevadmp.c</a>, -<a href="../devices/gdevbj10.c">devices/gdevbj10.c</a>, -<a href="../devices/gdevbjc.h">devices/gdevbjc.h</a>, -<a href="../devices/gdevbjcl.c">devices/gdevbjcl.c</a>, -<a href="../devices/gdevbjcl.h">devices/gdevbjcl.h</a>, -<a href="../devices/gdevccr.c">devices/gdevccr.c</a>, -<a href="../devices/gdevcdj.c">devices/gdevcdj.c</a>, -<a href="../devices/gdevclj.c">devices/gdevclj.c</a>, -<a href="../devices/gdevcljc.c">devices/gdevcljc.c</a>, -<a href="../devices/gdevcslw.c">devices/gdevcslw.c</a>, -<a href="../devices/gdevdjtc.c">devices/gdevdjtc.c</a>, -<a href="../devices/gdevdm24.c">devices/gdevdm24.c</a>, -<a href="../devices/gdevepsc.c">devices/gdevepsc.c</a>, -<a href="../devices/gdevepsn.c">devices/gdevepsn.c</a>, -<a href="../devices/gdevescp.c">devices/gdevescp.c</a>, -<a href="../devices/gdevhl7x.c">devices/gdevhl7x.c</a>, -<a href="../devices/gdevijs.c">devices/gdevijs.c</a>, -<a href="../devices/gdevimgn.c">devices/gdevimgn.c</a>, -<a href="../devices/gdevl31s.c">devices/gdevl31s.c</a>, -<a href="../devices/gdevlbp8.c">devices/gdevlbp8.c</a>, -<a href="../devices/gdevlp8k.c">devices/gdevlp8k.c</a>, -<a href="../devices/gdevlxm.c">devices/gdevlxm.c</a>, -<a href="../devices/gdevn533.c">devices/gdevn533.c</a>, -<a href="../devices/gdevo182.c">devices/gdevo182.c</a>, -<a href="../devices/gdevokii.c">devices/gdevokii.c</a>, -<a href="../devices/gdevpcl.c">devices/gdevpcl.c</a>, -<a href="../devices/gdevpcl.h">devices/gdevpcl.h</a>, -<a href="../devices/gdevphex.c">devices/gdevphex.c</a>, -<a href="../devices/gdevpjet.c">devices/gdevpjet.c</a>, -<a href="../devices/gdevsj48.c">devices/gdevsj48.c</a>, -<a href="../devices/gdevsppr.c">devices/gdevsppr.c</a>, -<a href="../devices/gdevstc.c">devices/gdevstc.c</a>, -<a href="../devices/gdevstc.h">devices/gdevstc.h</a>, -<a href="../devices/gdevstc1.c">devices/gdevstc1.c</a>, -<a href="../devices/gdevstc2.c">devices/gdevstc2.c</a>, -<a href="../devices/gdevstc3.c">devices/gdevstc3.c</a>, -<a href="../devices/gdevstc4.c">devices/gdevstc4.c</a>, -<a href="../devices/gdevtknk.c">devices/gdevtknk.c</a>, -<a href="../devices/gdevupd.c">devices/gdevupd.c</a>. - -<dt> -The special <code>rinkj</code> high-quality inkjet driver: -<dd> -<a href="../devices/gdevrinkj.c">devices/gdevrinkj.c</a>, -<a href="../base/gsequivc.c">base/gsequivc.c</a>, -<a href="../base/gsequivc.h">base/gsequivc.h</a>, -<a href="../devices/rinkj/evenbetter-rll.c">devices/rinkj/evenbetter-rll.c</a>, -<a href="../devices/rinkj/evenbetter-rll.h">devices/rinkj/evenbetter-rll.h</a>, -<a href="../devices/rinkj/rinkj-byte-stream.c">devices/rinkj/rinkj-byte-stream.c</a>, -<a href="../devices/rinkj/rinkj-byte-stream.h">devices/rinkj/rinkj-byte-stream.h</a>, -<a href="../devices/rinkj/rinkj-config.c">devices/rinkj/rinkj-config.c</a>, -<a href="../devices/rinkj/rinkj-config.h">devices/rinkj/rinkj-config.h</a>, -<a href="../devices/rinkj/rinkj-device.c">devices/rinkj/rinkj-device.c</a>, -<a href="../devices/rinkj/rinkj-device.h">devices/rinkj/rinkj-device.h</a>, -<a href="../devices/rinkj/rinkj-dither.c">devices/rinkj/rinkj-dither.c</a>, -<a href="../devices/rinkj/rinkj-dither.h">devices/rinkj/rinkj-dither.h</a>, -<a href="../devices/rinkj/rinkj-epson870.c">devices/rinkj/rinkj-epson870.c</a>, -<a href="../devices/rinkj/rinkj-epson870.h">devices/rinkj/rinkj-epson870.h</a>, -<a href="../devices/rinkj/rinkj-screen-eb.c">devices/rinkj/rinkj-screen-eb.c</a>, -<a href="../devices/rinkj/rinkj-screen-eb.h">devices/rinkj/rinkj-screen-eb.h</a>, -<a href="../lib/rinkj-2200-setup">lib/rinkj-2200-setup</a>. - -</dl> - -<h3><a name="PostScript_interpreter"></a>PostScript interpreter</h3> - -<p> -The PostScript interpreter is conceptually simple: in fact, an interpreter -that could execute "3 4 add =" and print "7" was running 3 weeks after the -first line of Ghostscript code was written. However, a number of -considerations make the code large and complex. - -<p> -The interpreter is designed to run in environments with very limited memory. -The main consequence of this is that it cannot allocate its stacks -(dictionary, execution, operand) as ordinary arrays, since the -user-specified stack size limit may be very large. Instead, it allocates -them as a linked list of blocks. See below for more details. - -<p> -The interpreter must never cause a C runtime error that it cannot trap. -Unfortunately, C implementations almost never provide the ability to trap -stack overflow. In order to put a fixed bound on the C stack size, the -interpreter never implements PostScript recursion by C recursion. This -means that any C code that logically needs to call the interpreter must -instead push a continuation (including all necessary state information) on -the PostScript execution stack, followed by the PostScript object to be -executed, and then <em>return</em> to the interpreter. (See <a -href="../psi/estack.h">psi/estack.h</a> for more details about -continuations.) Unfortunately, since PostScript Level 2 introduces streams -whose data source can be a PostScript procedure, any code that reads or -writes stream data must be prepared to suspend itself, storing all necessary -state in a continuation. There are some places where this is extremely -awkward, such as the scanner/parser. - -<p> -The use of continuations affects many places in the interpreter, and even -some places in the graphics library. For example, when processing an image, -one may need to call a PostScript procedure as part of mapping a CIE color -to a device color. Ghostscript uses a variety of dodges to handle this: for -example, in the case of CIE color mapping, all of the PostScript procedures -are pre-sampled and the results cached. The Adobe implementation limits -this kind of recursion to a fixed number of levels (5?): this would be -another acceptable approach, but at this point it would require far more -code restructuring than it would be worth. - -<p> -A significant amount of the PostScript language implementation is in fact -written in PostScript. Writing in PostScript leverages the C code for -multi-threading, garbage collection, error handling, continuations for -streams, etc., etc.; also, we have found PostScript in general more concise -and easier to debug than C, mostly because of memory management issues. So -given the choice, we tended to implement a feature in PostScript if it -worked primarily with PostScript data structures, wasn't heavily used -(example: font loading), or if it interacted with the stream or other -callback machinery (examples: ReusableFileDecode streams, resourceforall). -Often we would add non-standard PostScript operators for functions that had -to run faster or that did more C-like things, such as the media matching -algorithm for setpagedevice. - - - -<h4><a name="Main_program"></a>Main program</h4> - -<p> -The main program of the interpreter is normally invoked from the command -line, but it has an API as well. In fact, it has two APIs: one that -recognizes the existence of multiple "interpreter instances" (although it -currently provides a default instance, which almost all clients use), and a -completely different one designed for Windows DLLs. These should be unified -as soon as possible, since there are two steadily growing incompatible -bodies of client code. - -<dl> - -<dt> -Files: -<dd> -<a href="../psi/gs.c">psi/gs.c</a>, -<a href="../psi/gserver.c">psi/gserver.c</a>, -<a href="../psi/iinit.c">psi/iinit.c</a>, -<a href="../psi/iinit.h">psi/iinit.h</a>, -<a href="../psi/imain.c">psi/imain.c</a>, -<a href="../psi/imain.h">psi/imain.h</a>, -<a href="../psi/imainarg.c">psi/imainarg.c</a>, -<a href="../psi/imainarg.h">psi/imainarg.h</a>, -<a href="../psi/iminst.h">psi/iminst.h</a>, -<a href="../psi/main.h">psi/main.h</a>. - -</dl> - -<h4><a name="Data_structures"></a>Data structures</h4> - -<p> -The main data structures visible to the PostScript programmers are arrays, -contexts, dictionaries, names, and stacks. - -<p> -Arrays have no unusual properties. See under <a href="#Refs">Refs</a> below -for more information about how array elements are stored. - -<p> -Contexts are used to hold the interpreter state even in configurations that -don't include the Display PostScript multiple context extension. Context -switching is implemented by a complex cooperation of C and PostScript code. - -<p> -Dictionaries have two special properties worth noting: - -<ul> - -<li>They use an optimized storage representation if all the keys are names, -which is almost always the case. - -<li>They interact with a caching scheme used to accelerate name lookup in -the interpreter. - -</ul> - -<p> -Names are allocated in blocks. The characters and hash chains are stored -separately from the lookup cache information, so that in the future, most of -the former can be compiled into the executable and shared or put in ROM. -(This is not actually done yet.) - -<dl> - -<dt> -Contexts: -<dd> -<a href="../psi/icontext.c">psi/icontext.c</a>, -<a href="../psi/icontext.h">psi/icontext.h</a>, -<a href="../psi/icstate.h">psi/icstate.h</a>. - -<dt> -Dictionaries: -<dd> -<a href="../psi/iddict.h">psi/iddict.h</a>, -<a href="../psi/idict.h">psi/idict.h</a>, -<a href="../psi/idict.c">psi/idict.c</a>, -<a href="../psi/idictdef.h">psi/idictdef.h</a>, -<a href="../psi/idicttpl.h">psi/idicttpl.h</a>. - -<dt> -Names: -<dd> -<a href="../psi/iname.c">psi/iname.c</a>, -<a href="../psi/iname.h">psi/iname.h</a>, -<a href="../psi/inamedef.h">psi/inamedef.h</a>, -<a href="../psi/inameidx.h">psi/inameidx.h</a>, -<a href="../psi/inames.h">psi/inames.h</a>, -<a href="../psi/inamestr.h">psi/inamestr.h</a>. - -</dl> - -<h4><a name="Stacks"></a>Stacks</h4> - -<p> -As mentioned above, each stack is allocated as a linked list of blocks. -However, for reasonable performance, operators must normally be able to -access their operands and produce their results using indexing rather than -an access procedure. This is implemented by ensuring that all the operands -of an operator are in the topmost block of the stack, using guard entries -that cause an internal error if the condition isn't met. See <a -href="../psi/iostack.h">psi/iostack.h</a> for more details. - -<dl> - -<dt> -Generic stacks: -<dd> -<a href="../psi/isdata.h">psi/isdata.h</a>, -<a href="../psi/istack.c">psi/istack.c</a>, -<a href="../psi/istack.h">psi/istack.h</a>, -<a href="../psi/istkparm.h">psi/istkparm.h</a>. - -<dt> -Specific stacks: -<dd> - -<dl> - -<dt> -Dictionary stack: -<dd> -<a href="../psi/dstack.h">psi/dstack.h</a>, -<a href="../psi/iddstack.h">psi/iddstack.h</a>, -<a href="../psi/idsdata.h">psi/idsdata.h</a>, -<a href="../psi/idstack.c">psi/idstack.c</a>, -<a href="../psi/idstack.h">psi/idstack.h</a>. - -<dt> -Execution stack: -<dd> -<a href="../psi/estack.h">psi/estack.h</a>, -<a href="../psi/iesdata.h">psi/iesdata.h</a>, -<a href="../psi/iestack.h">psi/iestack.h</a>. - -<dt> -Operand stack: -<dd> -<a href="../psi/iosdata.h">psi/iosdata.h</a>, -<a href="../psi/iostack.h">psi/iostack.h</a>, -<a href="../psi/ostack.h">psi/ostack.h</a>. - -</dl> - -</dl> - -<h4><a name="Interpreter_loop"></a>Interpreter loop</h4> - -<dl> - -<dt> -Files: -<dd> -<a href="../psi/interp.c">psi/interp.c</a>, -<a href="../psi/interp.h">psi/interp.h</a>. - -</dl> - -<h4><a name="Scanning_parsing"></a>Scanning/parsing</h4> - -<p> -PostScript parsing consists essentially of token scanning, and is simple in -principle. The scanner is complex because it must be able to suspend its -operation at any time (i.e., between any two input characters) to allow an -interpreter callout, if its input is coming from a procedure-based stream -and the procedure must be called to provide more input data. - -<dl> - -<dt> -Main scanner: -<dd> -<a href="../psi/iscan.c">psi/iscan.c</a>, -<a href="../psi/iscan.h">psi/iscan.h</a>, -<a href="../psi/iscannum.c">psi/iscannum.c</a>, -<a href="../psi/iscannum.h">psi/iscannum.h</a>, -<a href="../base/scanchar.h">base/scanchar.h</a>, -<a href="../base/scantab.c">base/scantab.c</a>. - -<dt> -Binary tokens: -<dd> -<a href="../psi/btoken.h">psi/btoken.h</a>, -<a href="../psi/ibnum.c">psi/ibnum.c</a>, -<a href="../psi/ibnum.h">psi/ibnum.h</a>, -<a href="../psi/inobtokn.c">psi/inobtokn.c</a>, -<a href="../psi/iscanbin.c">psi/iscanbin.c</a>, -<a href="../psi/iscanbin.h">psi/iscanbin.h</a>. - -<dt> -DSC parsing: -<dd> -<a href="../psi/dscparse.c">psi/dscparse.c</a>, -<a href="../psi/dscparse.h">psi/dscparse.h</a>. - -</dl> - -<h4><a name="Standard_operators"></a>Standard operators</h4> - -<dl> - -<dt> -Non-output-related: -<dd> - -<dl> - -<dt> -Filters: -<dd> -<a href="../psi/ifilter.h">psi/ifilter.h</a>, -<a href="../psi/ifilter2.h">psi/ifilter2.h</a>, -<a href="../psi/ifrpred.h">psi/ifrpred.h</a>, -<a href="../psi/ifwpred.h">psi/ifwpred.h</a>, -<a href="../psi/istream.h">psi/istream.h</a>, -<a href="../psi/zfbcp.c">psi/zfbcp.c</a>, -<a href="../psi/zfdctd.c">psi/zfdctd.c</a>, -<a href="../psi/zfdcte.c">psi/zfdcte.c</a>, -<a href="../psi/zfdecode.c">psi/zfdecode.c</a>, -<a href="../psi/zfilter.c">psi/zfilter.c</a>, -<a href="../psi/zfilter2.c">psi/zfilter2.c</a>, -<a href="../psi/zfjbig2.c">psi/zfjbig2.c</a>, -<a href="../psi/zfjpx.c">psi/zfjpx.c</a>, -<a href="../psi/zfmd5.c">psi/zfmd5.c</a>, -<a href="../psi/zfarc4.c">psi/zfarc4.c</a>, -<a href="../psi/zfproc.c">psi/zfproc.c</a>, -<a href="../psi/zfrsd.c">psi/zfrsd.c</a>, -<a href="../psi/zfzlib.c">psi/zfzlib.c</a>. - -<dt> -File and stream I/O: -<dd> -<a href="../psi/files.h">psi/files.h</a>, -<a href="../psi/itoken.h">psi/itoken.h</a>, -<a href="../psi/zbseq.c">psi/zbseq.c</a>, -<a href="../psi/zdscpars.c">psi/zdscpars.c</a>, -<a href="../psi/zfile.h">psi/zfile.h</a>, -<a href="../psi/zfile.c">psi/zfile.c</a>, -<a href="../psi/zfile1.c">psi/zfile1.c</a>, -<a href="../psi/zfileio.c">psi/zfileio.c</a>, -<a href="../psi/ztoken.c">psi/ztoken.c</a>. - -<dt> -Data structures: -<dd> -<a href="../psi/zarray.c">psi/zarray.c</a>, -<a href="../psi/zdict.c">psi/zdict.c</a>, -<a href="../psi/zgeneric.c">psi/zgeneric.c</a>, -<a href="../psi/zpacked.c">psi/zpacked.c</a>, -<a href="../psi/zstring.c">psi/zstring.c</a>. - -<dt> -Functions: -<dd> -<a href="../psi/ifunc.h">psi/ifunc.h</a>, -<a href="../psi/zfunc.c">psi/zfunc.c</a>, -<a href="../psi/zfunc0.c">psi/zfunc0.c</a>, -<a href="../psi/zfunc3.c">psi/zfunc3.c</a>, -<a href="../psi/zfunc4.c">psi/zfunc4.c</a>, - -<dt> -Other: -<dd> -<a href="../psi/ivmem2.h">psi/ivmem2.h</a>, -<a href="../psi/zalg.c">psi/zalg.c</a>, -<a href="../psi/zarith.c">psi/zarith.c</a>, -<a href="../psi/zcontext.c">psi/zcontext.c</a>, -<a href="../psi/zcontrol.c">psi/zcontrol.c</a>, -<a href="../psi/zmath.c">psi/zmath.c</a>, -<a href="../psi/zmatrix.c">psi/zmatrix.c</a>, -<a href="../psi/zmisc.c">psi/zmisc.c</a>, -<a href="../psi/zmisc1.c">psi/zmisc1.c</a>, -<a href="../psi/zmisc2.c">psi/zmisc2.c</a>, -<a href="../psi/zmisc3.c">psi/zmisc3.c</a>, -<a href="../psi/zrelbit.c">psi/zrelbit.c</a>, -<a href="../psi/zstack.c">psi/zstack.c</a>, -<a href="../psi/ztype.c">psi/ztype.c</a>, -<a href="../psi/zusparam.c">psi/zusparam.c</a>, -<a href="../psi/zvmem.c">psi/zvmem.c</a>, -<a href="../psi/zvmem2.c">psi/zvmem2.c</a>. - -</dl> - -<dt> -Output-related: -<dd> - -<dl> - -<dt> -Device management: -<dd> -<a href="../psi/zdevcal.c">psi/zdevcal.c</a>, -<a href="../psi/zdevice.c">psi/zdevice.c</a>, -<a href="../psi/zdevice2.c">psi/zdevice2.c</a>, -<a href="../psi/ziodev.c">psi/ziodev.c</a>, -<a href="../psi/ziodev2.c">psi/ziodev2.c</a>, -<a href="../psi/ziodevs.c">psi/ziodevs.c</a>, -<a href="../psi/zmedia2.c">psi/zmedia2.c</a>, - -<dt> -Fonts and text: -<dd> -<a href="../psi/bfont.h">psi/bfont.h</a>, -<a href="../psi/ichar.h">psi/ichar.h</a>, -<a href="../psi/ichar1.h">psi/ichar1.h</a>, -<a href="../psi/icharout.h">psi/icharout.h</a>, -<a href="../psi/icid.h">psi/icid.h</a>, -<a href="../psi/ifcid.h">psi/ifcid.h</a>, -<a href="../psi/ifont.h">psi/ifont.h</a>, -<a href="../psi/ifont1.h">psi/ifont1.h</a>, -<a href="../psi/ifont2.h">psi/ifont2.h</a>, -<a href="../psi/ifont42.h">psi/ifont42.h</a>, -<a href="../psi/zbfont.c">psi/zbfont.c</a>, -<a href="../psi/zcfont.c">psi/zcfont.c</a>, -<a href="../psi/zchar.c">psi/zchar.c</a>, -<a href="../psi/zchar1.c">psi/zchar1.c</a>, -<a href="../psi/zchar2.c">psi/zchar2.c</a>, -<a href="../psi/zchar32.c">psi/zchar32.c</a>, -<a href="../psi/zchar42.c">psi/zchar42.c</a>, -<a href="../psi/zchar42.h">psi/zchar42.h</a>, -<a href="../psi/zcharout.c">psi/zcharout.c</a>, -<a href="../psi/zcharx.c">psi/zcharx.c</a>, -<a href="../psi/zcid.c">psi/zcid.c</a>, -<a href="../psi/zfcid.c">psi/zfcid.c</a>, -<a href="../psi/zfcid0.c">psi/zfcid0.c</a>, -<a href="../psi/zfcid1.c">psi/zfcid1.c</a>, -<a href="../psi/zfcmap.c">psi/zfcmap.c</a>, -<a href="../psi/zfont.c">psi/zfont.c</a>, -<a href="../psi/zfont0.c">psi/zfont0.c</a>, -<a href="../psi/zfont1.c">psi/zfont1.c</a>, -<a href="../psi/zfont2.c">psi/zfont2.c</a>, -<a href="../psi/zfont32.c">psi/zfont32.c</a>, -<a href="../psi/zfont42.c">psi/zfont42.c</a>, -<a href="../psi/zfontenum.c">psi/zfontenum.c</a>. - -<dt> -A bridge to the True Type bytecode interpreter: -<dd> -<a href="../base/gxttfb.c">base/gxttfb.c</a>, -<a href="../base/gxttfb.h">base/gxttfb.h</a>, -<a href="../base/ttfoutl.h">base/ttfoutl.h</a>, -<a href="../base/ttfmain.c">base/ttfmain.c</a>, -<a href="../base/ttfmemd.c">base/ttfmemd.c</a>, -<a href="../base/ttfmemd.h">base/ttfmemd.h</a>, -<a href="../base/ttfinp.c">base/ttfinp.c</a>, -<a href="../base/ttfinp.h">base/ttfinp.h</a>. - -<dt> -A reduced True Type bytecode interpreter: -<br><em>(this is based in part on the work of the Freetype Team and incorporates some code from -the -FreeType 1 project)</em> -<dd> -<a href="../base/ttfsfnt.h">base/ttfsfnt.h</a>, -<a href="../base/ttcalc.c">base/ttcalc.c</a>, -<a href="../base/ttcalc.h">base/ttcalc.h</a>, -<a href="../base/ttcommon.h">base/ttcommon.h</a>, -<a href="../base/ttconf.h">base/ttconf.h</a>, -<a href="../base/ttconfig.h">base/ttconfig.h</a>, -<a href="../base/ttinterp.c">base/ttinterp.c</a>, -<a href="../base/ttinterp.h">base/ttinterp.h</a>, -<a href="../base/ttload.c">base/ttload.c</a>, -<a href="../base/ttload.h">base/ttload.h</a>, -<a href="../base/ttmisc.h">base/ttmisc.h</a>, -<a href="../base/ttobjs.c">base/ttobjs.c</a>, -<a href="../base/ttobjs.h">base/ttobjs.h</a>, -<a href="../base/tttables.h">base/tttables.h</a>, -<a href="../base/tttype.h">base/tttype.h</a>, -<a href="../base/tttypes.h">base/tttypes.h</a>. - -<dt> -Color, pattern, and halftone: -<dd> -<a href="../psi/icie.h">psi/icie.h</a>, -<a href="../psi/icolor.h">psi/icolor.h</a>, -<a href="../psi/icremap.h">psi/icremap.h</a>, -<a href="../psi/icsmap.h">psi/icsmap.h</a>, -<a href="../psi/iht.h">psi/iht.h</a>, -<a href="../psi/ipcolor.h">psi/ipcolor.h</a>, -<a href="../psi/zcie.c">psi/zcie.c</a>, -<a href="../psi/zcolor.c">psi/zcolor.c</a>, -<a href="../psi/zcolor1.c">psi/zcolor1.c</a>, -<a href="../psi/zcolor2.c">psi/zcolor2.c</a>, -<a href="../psi/zcolor3.c">psi/zcolor3.c</a>, -<a href="../psi/zcrd.c">psi/zcrd.c</a>, -<a href="../psi/zcsindex.c">psi/zcsindex.c</a>, -<a href="../psi/zcspixel.c">psi/zcspixel.c</a>, -<a href="../psi/zcssepr.c">psi/zcssepr.c</a>, -<a href="../psi/zicc.c">psi/zicc.c</a>, -<a href="../psi/zht.c">psi/zht.c</a>, -<a href="../psi/zht1.c">psi/zht1.c</a>, -<a href="../psi/zht2.h">psi/zht2.h</a>, -<a href="../psi/zht2.c">psi/zht2.c</a>, -<a href="../psi/zpcolor.c">psi/zpcolor.c</a>, -<a href="../psi/zshade.c">psi/zshade.c</a>, -<a href="../psi/ztrans.c">psi/ztrans.c</a>. - -<dt> -Images: -<dd> -<a href="../psi/iimage.h">psi/iimage.h</a>, -<a href="../psi/zimage.c">psi/zimage.c</a>, -<a href="../psi/zimage3.c">psi/zimage3.c</a>, -<a href="../psi/zfimscale.c">psi/zfimscale.c</a>. - -<dt> -Other graphics: -<dd> -<a href="../psi/igstate.h">psi/igstate.h</a>, -<a href="../psi/zdpnext.c">psi/zdpnext.c</a>, -<a href="../psi/zdps.c">psi/zdps.c</a>, -<a href="../psi/zdps1.c">psi/zdps1.c</a>, -<a href="../psi/zgstate.c">psi/zgstate.c</a>, -<a href="../psi/zpaint.c">psi/zpaint.c</a>, -<a href="../psi/zpath.c">psi/zpath.c</a>, -<a href="../psi/zpath1.c">psi/zpath1.c</a>, -<a href="../psi/ztrap.c">psi/ztrap.c</a>, -<a href="../psi/zupath.c">psi/zupath.c</a>. - -</dl> - -<dt> -Operator support: -<dd> -<a href="../psi/oparc.h">psi/oparc.h</a>, -<a href="../psi/opcheck.h">psi/opcheck.h</a>, -<a href="../psi/opdef.h">psi/opdef.h</a>, -<a href="../psi/oper.h">psi/oper.h</a>, -<a href="../psi/opextern.h">psi/opextern.h</a>. - -</dl> - -<h4><a name="Non_standard_operators"></a>Non-standard operators</h4> - -<p> -The interpreter includes many non-standard operators. Most of these provide -some part of the function of a standard operator, so that the standard -operator itself can be implemented in PostScript: these are not of interest -to users, and their function is usually obvious from the way they are used. -However, some non-standard operators provide access to additional, -non-standard facilities that users might want to know about, such as -transparency, RasterOp, and in-memory rendering. These are documented at <a -href="Language.htm#Additional_operators">Language.htm#Additional_operators</a>. - -<p> -We don't document the complete set of non-standard operators here, because -the set changes frequently. However, all non-standard operators are -supposed to have names that begin with '.', so you can find them all by -executing the following (Unix) command: - -<blockquote><pre> -grep '{".[.]' psi/[zi]*.c -</pre></blockquote> - -<p> -In addition to individual non-standard operators implemented in the same -files as standard ones, there are several independent optional packages of -non-standard operators. As with other non-standard operators, the names of -all the operators in these packages begin with '.'. We list those packages -here. - -<dl> - -<dt> -<a href="../psi/zdouble.c">psi/zdouble.c</a> -<dd> -Provides "double" floating point arithmetic, using 8-byte strings to hold -values. Developed under a contract; probably used only by the group that -funded the development. - -<dt> -<a href="../psi/zfsample.c">psi/zfsample.c</a>, -<dd> -Provides a special operator to sample a given function and create a new type 0 function. - -<dt> -<a href="../psi/zsysvm.c">psi/zsysvm.c</a> -<dd> -Provides operators for allocating objects in specific VM spaces, -disregarding the current VM mode. - -</dl> - -<h4><a name="Interpreter_support"></a>Interpreter support</h4> - -<p> -Memory management (refs, GC, save/restore) -- see <a -href="#PostScript_interpreter_extensions">below</a>. - -<dl> -<dt> -Font API : -<dd> -<a href="../psi/ifapi.h">psi/ifapi.h</a>, -<a href="../psi/zfapi.c">psi/zfapi.c</a>, -<a href="../base/fapiufst.c">base/fapiufst.c</a>, -<a href="../base/fapi_ft.c">base/fapi_ft.c</a>, -<a href="../base/wrfont.h">base/wrfont.h</a>, -<a href="../base/wrfont.c">base/wrfont.c</a>, -<a href="../base/write_t1.h">base/write_t1.h</a>, -<a href="../base/write_t1.c">base/write_t1.c</a>, -<a href="../base/write_t2.h">base/write_t2.h</a>, -<a href="../base/write_t2.c">base/write_t2.c</a>, - -<dt> -Miscellaneous support: -<dd> -<a href="../psi/ierrors.h">psi/ierrors.h</a>, -<a href="../base/gserrors.h">base/gserrors.h</a>, -<a href="../psi/ghost.h">psi/ghost.h</a>, -<a href="../psi/iconf.c">psi/iconf.c</a>, -<a href="../psi/iconf.h">psi/iconf.h</a>, -<a href="../psi/idparam.c">psi/idparam.c</a>, -<a href="../psi/idparam.h">psi/idparam.h</a>, -<a href="../psi/ilevel.h">psi/ilevel.h</a>, -<a href="../psi/inouparm.c">psi/inouparm.c</a>, -<a href="../psi/iparam.c">psi/iparam.c</a>, -<a href="../psi/iparam.h">psi/iparam.h</a>, -<a href="../psi/iparray.h">psi/iparray.h</a>, -<a href="../psi/iutil.c">psi/iutil.c</a>, -<a href="../psi/iutil.h">psi/iutil.h</a>, -<a href="../psi/iutil2.c">psi/iutil2.c</a>, -<a href="../psi/iutil2.h">psi/iutil2.h</a>, -<a href="../psi/iplugin.c">psi/iplugin.c</a>, -<a href="../psi/iplugin.h">psi/iplugin.h</a>. - -</dl> - -<h4><a name="PostScript_code"></a>PostScript code</h4> - -<dl> - -<dt> -Initialization and language support: -<dd> - -<dl> - -<dt> -All configurations: -<dd> -<a href="../Resource/Init/gs_init.ps">Resource/Init/gs_init.ps</a>, -<a href="../Resource/Init/gs_statd.ps">Resource/Init/gs_statd.ps</a>. - -<dt> -Level 2: -<dd> -<a href="../Resource/Init/gs_btokn.ps">Resource/Init/gs_btokn.ps</a>, -<a href="../Resource/Init/gs_dps1.ps">Resource/Init/gs_dps1.ps</a>, -<a href="../Resource/Init/gs_dps2.ps">Resource/Init/gs_dps2.ps</a>, -<a href="../Resource/Init/gs_lev2.ps">Resource/Init/gs_lev2.ps</a>, -<a href="../Resource/Init/gs_res.ps">Resource/Init/gs_res.ps</a>, -<a href="../Resource/Init/gs_resmp.ps">Resource/Init/gs_resmp.ps</a>, -<a href="../Resource/Init/gs_setpd.ps">Resource/Init/gs_setpd.ps</a>. - -<dt> -LanguageLevel 3: -<dd> -<a href="../Resource/Init/gs_frsd.ps">Resource/Init/gs_frsd.ps</a>, -<a href="../Resource/Init/gs_ll3.ps">Resource/Init/gs_ll3.ps</a>, -<a href="../Resource/Init/gs_trap.ps">Resource/Init/gs_trap.ps</a>. - -<dt> -Display PostScript: -<dd> -<a href="../Resource/Init/gs_dpnxt.ps">Resource/Init/gs_dpnxt.ps</a>, -<a href="../Resource/Init/gs_dps.ps">Resource/Init/gs_dps.ps</a>. - -<dt> -Emulation of other interpreters: -<dd> -<a href="../Resource/Init/gs_cet.ps">Resource/Init/gs_cet.ps</a> (Adobe CPSI). - -</dl> - -<dt> -Color Spaces and support: -<dd> - -<dl> - -<dt> -Color Space Loading: -<dd> -<a href="../Resource/Init/gs_cspace.ps">Resource/Init/gs_cspace.ps</a>, - -<dt> -ICC color profiles: -<dd> -<a href="../Resource/Init/gs_icc.ps">Resource/Init/gs_icc.ps</a>. - -</dl> - -<dt> -Font loading and support: -<dd> - -<dl> - -<dt> -Font name mapping: -<dd> -<a href="../Resource/Init/Fontmap">Resource/Init/Fontmap</a>, -<a href="../lib/Fontmap.ATB">lib/Fontmap.ATB</a>, -<a href="../lib/Fontmap.ATM">lib/Fontmap.ATM</a>, -<a href="../Resource/Init/Fontmap.GS">Resource/Init/Fontmap.GS</a>, -<a href="../lib/Fontmap.OS2">lib/Fontmap.OS2</a>, -<a href="../lib/Fontmap.OSF">lib/Fontmap.OSF</a>, -<a href="../lib/Fontmap.SGI">lib/Fontmap.SGI</a>, -<a href="../lib/Fontmap.Sol">lib/Fontmap.Sol</a>, -<a href="../lib/Fontmap.Ult">lib/Fontmap.Ult</a>, -<a href="../lib/Fontmap.VMS">lib/Fontmap.VMS</a>, -<a href="../lib/Fontmap.URW-136.T1">lib/Fontmap.URW-136.T1</a>, -<a href="../lib/Fontmap.URW-136.TT">lib/Fontmap.URW-136.TT</a>, -<a href="../Resource/Init/cidfmap">Resource/Init/cidfmap</a>, -<a href="../Resource/Init/FAPIcidfmap">Resource/Init/FAPIcidfmap</a>, -<a href="../Resource/Init/FAPIfontmap">Resource/Init/FAPIfontmap</a>, -<a href="../Resource/Init/FCOfontmap-PCLPS2">Resource/Init/FCOfontmap-PCLPS2</a>. - -<dt> -Generic: -<dd> -<a href="../Resource/Init/gs_fonts.ps">Resource/Init/gs_fonts.ps</a>, -<a href="../Resource/Init/gs_fntem.ps">Resource/Init/gs_fntem.ps</a>. - -<dt> -Type 1 and CFF: -<dd> -<a href="../Resource/Init/gs_cff.ps">Resource/Init/gs_cff.ps</a>, -<a href="../Resource/Init/gs_diskf.ps">Resource/Init/gs_diskf.ps</a>, -<a href="../Resource/Init/gs_type1.ps">Resource/Init/gs_type1.ps</a>. - -<dt> -TrueType: -<dd> -<a href="../Resource/Init/gs_ttf.ps">Resource/Init/gs_ttf.ps</a>, -<a href="../Resource/Init/gs_typ42.ps">Resource/Init/gs_typ42.ps</a>. - -<dt> -CID-keyed: -<dd> -<a href="../Resource/Init/gs_cidcm.ps">Resource/Init/gs_cidcm.ps</a>, -<a href="../Resource/Init/gs_cidfn.ps">Resource/Init/gs_cidfn.ps</a>, -<a href="../Resource/Init/gs_cmap.ps">Resource/Init/gs_cmap.ps</a>, -<a href="../Resource/Init/gs_ciddc.ps">Resource/Init/gs_ciddc.ps</a>, -<a href="../Resource/Init/gs_cidfm.ps">Resource/Init/gs_cidfm.ps</a>, -<a href="../Resource/Init/gs_cidtt.ps">Resource/Init/gs_cidtt.ps</a>. - -<dt> -Font API: -<dd> -<a href="../Resource/Init/gs_fapi.ps">Resource/Init/gs_fapi.ps</a>, -<a href="../Resource/Init/FAPIconfig">Resource/Init/FAPIconfig</a>, -<a href="../lib/FAPIconfig-FCO">lib/FAPIconfig-FCO</a>, -<a href="../Resource/Init/xlatmap">Resource/Init/xlatmap</a>. -<a href="../Resource/Init/FCOfontmap-PCLPS2">Resource/Init/FCOfontmap-PCLPS2</a>. -<a href="../lib/FCOfontmap-PCLPS3">lib/FCOfontmap-PCLPS3</a>. -<a href="../lib/FCOfontmap-PS3">lib/FCOfontmap-PS3</a>. - -<dt> -Other: -<dd> -<a href="../lib/gs_kanji.ps">lib/gs_kanji.ps</a>, -<a href="../lib/gs_pfile.ps">lib/gs_pfile.ps</a>, -<a href="../Resource/Init/gs_typ32.ps">Resource/Init/gs_typ32.ps</a>. - -</dl> - -<dt> -Encodings: -<dd> - -<dl> - -<dt> -Adobe-specified: -<dd> -<a href="../lib/gs_ce_e.ps">lib/gs_ce_e.ps</a>, -<a href="../Resource/Init/gs_dbt_e.ps">Resource/Init/gs_dbt_e.ps</a>, -<a href="../Resource/Init/gs_il1_e.ps">Resource/Init/gs_il1_e.ps</a>, -<a href="../Resource/Init/gs_mex_e.ps">Resource/Init/gs_mex_e.ps</a>, -<a href="../Resource/Init/gs_mro_e.ps">Resource/Init/gs_mro_e.ps</a>, -<a href="../Resource/Init/gs_pdf_e.ps">Resource/Init/gs_pdf_e.ps</a>, -<a href="../Resource/Init/gs_std_e.ps">Resource/Init/gs_std_e.ps</a>, -<a href="../Resource/Init/gs_sym_e.ps">Resource/Init/gs_sym_e.ps</a>, -<a href="../Resource/Init/gs_wan_e.ps">Resource/Init/gs_wan_e.ps</a>. - -<dt> -Additional: -<dd> -<a href="../lib/gs_il2_e.ps">lib/gs_il2_e.ps</a>, -<a href="../lib/gs_ksb_e.ps">lib/gs_ksb_e.ps</a>, -<a href="../lib/gs_wl1_e.ps">lib/gs_wl1_e.ps</a>, -<a href="../lib/gs_wl2_e.ps">lib/gs_wl2_e.ps</a>, -<a href="../lib/gs_wl5_e.ps">lib/gs_wl5_e.ps</a>. - -<dt> -Pseudo-encodings for internal use: -<dd> -<a href="../lib/gs_lgo_e.ps">lib/gs_lgo_e.ps</a>, -<a href="../lib/gs_lgx_e.ps">lib/gs_lgx_e.ps</a>, -<a href="../Resource/Init/gs_mgl_e.ps">Resource/Init/gs_mgl_e.ps</a>. - -</dl> - -<dt> -Miscellaneous: -<dd> - -<dl> - -<dt> -Image support: -<dd> -<a href="../Resource/Init/gs_img.ps">Resource/Init/gs_img.ps</a>, - -<dt> -Emulation of %disk IODevice: -<dd> -<a href="../Resource/Init/gs_diskn.ps">Resource/Init/gs_diskn.ps</a>, - -<dt> -Other support: -<dd> -<a href="../Resource/Init/gs_agl.ps">Resource/Init/gs_agl.ps</a>, -<a href="../Resource/Init/gs_dscp.ps">Resource/Init/gs_dscp.ps</a>, -<a href="../Resource/Init/gs_epsf.ps">Resource/Init/gs_epsf.ps</a>, -<a href="../Resource/Init/gs_pdfwr.ps">Resource/Init/gs_pdfwr.ps</a>, -<a href="../lib/gs_rdlin.ps">lib/gs_rdlin.ps</a>. - -<dt> -X Windows icon bitmaps: -<dd> -<a href="../lib/gs_l.xbm">lib/gs_l.xbm</a>, -<a href="../lib/gs_l.xpm">lib/gs_l.xpm</a>, -<a href="../lib/gs_l_m.xbm">lib/gs_l_m.xbm</a>, -<a href="../lib/gs_m.xbm">lib/gs_m.xbm</a>, -<a href="../lib/gs_m.xpm">lib/gs_m.xpm</a>, -<a href="../lib/gs_m_m.xbm">lib/gs_m_m.xbm</a>, -<a href="../lib/gs_s.xbm">lib/gs_s.xbm</a>, -<a href="../lib/gs_s.xpm">lib/gs_s.xpm</a>, -<a href="../lib/gs_s_m.xbm">lib/gs_s_m.xbm</a>, -<a href="../lib/gs_t.xbm">lib/gs_t.xbm</a>, -<a href="../lib/gs_t.xpm">lib/gs_t.xpm</a>, -<a href="../lib/gs_t_m.xbm">lib/gs_t_m.xbm</a>. - -<dt> -PDF/X-3 definition file sample : -<dd> -<a href="../lib/PDFX_def.ps">lib/PDFX_def.ps</a>, - -</dl> - -</dl> - -<h3><a name="PDF_interpreter"></a>PDF interpreter</h3> - -<p> -Ghostscript's PDF interpreter is written entirely in PostScript, because its -data structures are the same as PostScript's, and it is much more convenient -to manipulate PostScript-like data structures in PostScript than in C. -There is definitely a performance cost, but apparently not a substantial -one: we considered moving the main interpreter loop (read a token using -slightly different syntax than PostScript, push it on the stack if literal, -look it up in a special dictionary for execution if not) into C, but we did -some profiling and discovered that this wasn't accounting for enough of the -time to be worthwhile. - -<p> -Until recently, there was essentially no C code specifically for the purpose -of supporting PDF interpretation. The one major exception is the PDF 1.4 -transparency features, which we (but not Adobe) have made available to -PostScript code. - -<p> -In addition to patching the <code>run</code> operator to detect PDF -files, the interpreter provides some procedures in <a -href="../Resource/Init/pdf_main.ps">Resource/Init/pdf_main.ps</a> that are meant to be called -from applications such as previewers. - -<dl> - -<dt> -Files: -<dd> -<a href="../Resource/Init/pdf_base.ps">Resource/Init/pdf_base.ps</a>, -<a href="../Resource/Init/pdf_draw.ps">Resource/Init/pdf_draw.ps</a>, -<a href="../Resource/Init/pdf_font.ps">Resource/Init/pdf_font.ps</a>, -<a href="../Resource/Init/pdf_main.ps">Resource/Init/pdf_main.ps</a>, -<a href="../Resource/Init/pdf_rbld.ps">Resource/Init/pdf_rbld.ps</a>, -<a href="../Resource/Init/pdf_ops.ps">Resource/Init/pdf_ops.ps</a>, -<a href="../Resource/Init/pdf_sec.ps">Resource/Init/pdf_sec.ps</a>. -</dl> - -<h3><a name="PPD"></a>PostScript Printer Description</h3> -<p> -A PostScript Printer Description tells a generic PostScript printer -driver how to generate PostScript for a particular printer. -Ghostscript includes a PPD file for generating PostScript -intended to be converted to PDF. A Windows INF file for -installing the PPD on Windows 2000 and XP is included. - -<dl> - -<dt> -Files: -<dd> -<a href="../lib/ghostpdf.ppd">lib/ghostpdf.ppd</a>, -<a href="../lib/ghostpdf.inf">lib/ghostpdf.inf</a>, -<a href="../lib/ghostpdf.cat">lib/ghostpdf.cat</a>, -<a href="../lib/ghostpdf.README">lib/ghostpdf.README</a>. - -</dl> - -<h3><a name="Build_process"></a>Build process</h3> - -<h4><a name="Makefile_structure"></a>Makefile structure</h4> - -<p> -Ghostscript's makefiles embody a number of design decisions and assumptions -that may not be obvious from a casual reading of the code. - -<ul> - -<li>All files are stored in subdirectories. The names of all subdirectories -used in the build process are defined in the top-level makefiles for the -various platforms: there are no "hard wired" directory names in any makefile -rule. Subdirectory names in the makefiles are relative to the directory -that is current at build time: normally this directory is the parent of the -various subdirectories, and holds only a <code>makefile</code>, which in -turn simply references the real top-level makefile in the source -subdirectory. - -<li>All compiler and linker switches are likewise defined by macros, again -preferably in the top-level platform makefile. - -<li>There is an absolute distinction between "source-like" subdirectories, -which are read-only during the build process, and "object-like" -subdirectories, all of whose contents are generated by the build process and -which can be emptied (<code>rm *</code>) at any time with no bad -effects. The source subdirectories are defined by macros named -<code>xxxSRCDIR</code>. - -<li>Object subdirectories may distinguish further between those that hold -the results of the build process that are needed at run time (i.e., that -should be included in a run-time distribution), defined by -<code>BINDIR</code>, and those that are not needed at run time, defined -by <code>xxxGENDIR</code> and <code>xxxOBJDIR</code>. (The -distinction between these is historical and probably no longer relevant.) - -<li>There may be multiple object subdirectories for different build -configurations. On Unix, the <code>obj</code> and <code>bin</code> -directories are used for normal production builds, the -<code>debugobj</code> directory for debugging builds, and the -<code>pgobj</code> directory for profiling builds; other platforms may -use different conventions. The Unix makefiles support targets named -<code>debug</code> and <code>pg</code> for debugging and profiling -builds respectively; other platforms generally do not. - -<li>Makefiles will be maintained by hand. This requires editing the -following makefile elements whenever the relevant source files changes: - -<ul> - -<li>Every header (.h) file must have a corresponding macro definition in a -makefile. If <code>abc.h</code> #includes <code>def.h</code> and -<code>xyz.h</code>, the definition must have the form - -<blockquote><pre> -xyz_h=$(xxxSRCD)xyz.h $(def_h) $(xyz_h) -</pre></blockquote> - -where <code>xxxSRCD</code> is the macro defining the relevant source -directory (including a trailing '/'). Note that the '.' in the file name -has been replaced by an underscore. Note also that the definition must -follow all definitions it references, since some <code>make</code> -programs expand macros in definitions at the time of definition rather than -at the time of use. - -<li>Every .c file must have a corresponding rule in a makefile. If -<code>abc.c</code> #includes <code>def.h</code> and -<code>lmn.h</code>, the rule must have approximately the form - -<blockquote><pre> -$(xxxOBJD)abc.$(OBJ) : $(xxxSRCD)abc.c $(def_h) $(lmn_h) - $(xxCC) $(xxO_)abc.$(OBJ) $(C_) $(xxxSRCD)abc.c -</pre></blockquote> - -where <code>xxxSRCD</code> is as before; <code>xxxOBJD</code> is the -relevant object directory; <code>xxCC</code> defines the name of the C -compiler plus the relevant compilation switches; and <code>xxO_</code> -and <code>C_</code> are macros used to bridge syntactic differences -between different <code>make</code> programs. - -</ul> - -</ul> - -<p> -The requirement to keep makefiles up to date by hand has been controversial. -Two alternatives are generally proposed. - -<ul> - -<li>Programs like <code>makedeps</code>, which generate build rules -automatically from the #include lists in C files. We have found such -programs useless: they "wire in" specific, concrete directory names, not -only for our own code but even for the system header files; they have to be -run manually whenever code files are added, renamed, or deleted, or whenever -the list of #includes in any file changes; and they cannot deal with -different source files requiring different compilation switches. - -<li>MSVC-style "project" files. These are equally useless: they are not -portable across different vendors' tools -- in fact, there may not even be a -usable import/export facility to convert their data to or from text form -- -and they cannot combine configuration-independent data with -configuration-specific data. - -</ul> - -<p> -We have seriously considered writing our own build program in Tcl or Python -that would eliminate these problems, or perhaps porting the tools developed -by Digital's Vesta research project (if we can get access to them); however, -either of these approaches would create potential portability problems of -its own, not to mention difficulties in integrating with others' build -systems. - -<p> -For more information about makefiles: - -<ul> - -<li>For a detailed list of makefiles, and a discussion of makefile issues -related to portability, see the <a href="#Makefiles">Makefiles</a> section -below. - -<li>For more detailed information about editing configuration information in -makefiles, see <a -href="Make.htm#Makefile_overview">doc/Make.htm#Makefile_overview</a>. - -<li>For a complete example of adding a new driver to a makefile, see <a -href="Drivers.htm#Adding_drivers">doc/Drivers.htm#Adding_drivers</a>. - -<li>For a few more notes on makefile coding conventions, see <a -href="C-style.htm#Makefiles">doc/C-style.htm#Makefiles</a>. - -</ul> - -<h4><a name="dev_files"></a>.dev files</h4> - -<p> -On top of the general conventions just described, Ghostscript's makefiles -add a further layer of structure in order to support an open-ended set of -fine-grained, flexible configuration options. Selecting an option (usually -called a "module") for inclusion in the build may affect the build in many -ways: - -<ul> - -<li>Almost always, it requires linking in some compiled code files. - -<li>It may require running some additional initialization procedures at -startup. - -<li>It may require reading in some additional PostScript files at startup. -For example, a Level 2 PostScript build requires support for PostScript -resources and for setpagedevice, which are implemented in PostScript code. - -<li>It may require adding entries to a variety of internal tables that -catalogue such things as drivers, IODevices, Function types, etc. - -<li>It may require that other particular modules be included. For example, -the "PostScript Level 2" module requires the modules for various filters, -color spaces, etc. - -<li>It may require <em>removing</em> some other (default) module from the -build. For example, the core (Level 1) PostScript build has a "stub" for -binary tokens, which are a Level 2 feature but are referenced by the core -scanner: a Level 2 build must remove the stub. For more information about -this, look for the string <code>-replace</code> in the makefiles and in -<a href="../base/genconf.c">base/genconf.c</a>. - -</ul> - -<p> -Each module is defined in the makefiles by rules that create a file named -<code><em>xxx</em>.dev</code>. The dependencies of the rule include all -the files that make up the module (compiled code files, PostScript files, -etc.); the body of the rule creates the .dev file by writing the description -of the module into it. A program called <code>genconf</code>, described -in the next section, merges all the relevant .dev files together. For -examples of .dev rules, see any of the Ghostscript makefiles. - -<p> -Ultimately, a person must specify the root set of modules to include in a -build (which of course may require other modules, recursively). -Ghostscript's makefiles do this with a set of macros called -<code>FEATURE_DEVS</code> and <code>DEVICE_DEVS</code><em>n</em>, -defined in each top-level makefile, but nothing in the module machinery -depends on this. - -<h4><a name="Generators"></a>Generators</h4> - -<p> -Ghostscript's build procedure is somewhat unusual in that it compiles and -then executes some support programs during the build process. These -programs then generate data or source code that is used later on in the -build. - -<p> -The most important and complex of the generator programs is -<code>genconf</code>. <code>genconf</code> merges all the .dev files -that make up the build, and creates three or more output files used in later -stages: - -<ul> - -<li><code>gconfig.h</code>, consisting mainly of macro calls, one call -per "resource" making up the build, other than "resources" listed in the -other output files. - -<li><code>gconfigf.h</code>, produced only for PostScript builds with -compiled-in fonts, consisting of one macro call per font. - -<li>A linker control file whose name varies from one platform to another, -containing the list of compiled code files to be linked. - -<li>If necessary, another linker control file, also varying between -platforms, that contains other information for the linker such as the list -of system libraries to be searched. (On Unix platforms, the two linker -control functions are combined in a single file.) - -</ul> - -<dl> - -<dt> -Source generators: -<dd> - -<dl> - -<dt> -<a href="../base/genarch.c">base/genarch.c</a> -<dd> -Creates a header file containing a variety of information about the hardware -and compiler that isn't provided in any standard system header file. Always -used. - -<dt> -<a href="../base/genconf.c">base/genconf.c</a> (also generates non-source) -<dd> -Constructs header files and linker control files from the collection of -options and modules that make up the build. See above. Always used. - -<dt> -<a href="../base/genht.c">base/genht.c</a> -<dd> -Converts a PostScript halftone (in a particular constrained format) to a C -data structure that can be compiled into an executable. Only used if any -such halftones are included in the build. - -<dt> -<a href="../base/mkromfs.c">base/mkromfs.c</a> -<dd> -Takes a set of directories, and creates a compressed filesystem -image that can be compiled into the executable as static data and accessed -through the %rom% iodevice prefix. This is used to implement the -<code>COMPILE_INITS=1</code> feature (a compressed init fileset is more -efficient than the current 'gsinit.c' produced by 'geninit.c'). This IODevice -is more versatile since other files can be encapsulated such as fonts, helper -PostScript files and Resources. The list of files is defined in part in -<a href="../psi/psromfs.mak">psi/psromfs.mak</a>. - -</dl> - -<dt> -Other generators: -<dd> - -<dl> - -<dt> -<a href="../base/echogs.c">base/echogs.c</a> -<dd> -Implements a variety of shell-like functions to get around quirks, -limitations, and omissions in the shells on various platforms. Always used. - -<dt> -<a href="../base/genconf.c">base/genconf.c</a> (also generates source) -<dd> -See above. - -<dt> -<a href="../base/gendev.c">base/gendev.c</a> (not used) -<dd> -Was intended as a replacement for <code>genconf</code>, but was never -completed. - -</dl> - -</dl> - -<h4><a name="Build_support"></a>Support</h4> - -<p> -There are a number of programs, scripts, and configuration files that exist -only for the sake of the build process. - -<dl> - -<dt> -Files for PC environments: -<dd> -<a href="../base/gswin.icx">base/gswin.icx</a>, -<a href="../base/gswin16.icx">base/gswin16.icx</a>, -<a href="../base/bcc32.cfg">base/bcc32.cfg</a>, -<a href="../base/cp.bat">base/cp.bat</a>, -<a href="../base/cp.cmd">base/cp.cmd</a>, -<a href="../psi/dw32c.def">psi/dw32c.def</a>, -<a href="../psi/dwmain.rc">psi/dwmain.rc</a>, -<a href="../psi/dwmain32.def">psi/dwmain32.def</a>, -<a href="../psi/dwsetup.def">psi/dwsetup.def</a>, -<a href="../psi/dwsetup_x86.manifest">psi/dwsetup_x86.manifest</a>, -<a href="../psi/dwsetup_x64.manifest">psi/dwsetup_x64.manifest</a>, -<a href="../psi/dwuninst.def">psi/dwuninst.def</a>, -<a href="../psi/dwuninst_x86.manifest">psi/dwuninst_x86.manifest</a>, -<a href="../psi/dwuninst_x64.manifest">psi/dwuninst_x64.manifest</a>, -<a href="../psi/gsdll2.def">psi/gsdll2.def</a>, -<a href="../psi/gsdll2.rc">psi/gsdll2.rc</a>, -<a href="../psi/gsdll32.def">psi/gsdll32.def</a>, -<a href="../psi/gsdll32.rc">psi/gsdll32.rc</a>, -<a href="../psi/gsdll32w.lnk">psi/gsdll32w.lnk</a>, -<a href="../psi/gsos2.def">psi/gsos2.def</a>, -<a href="../psi/gsos2.icx">psi/gsos2.icx</a>, -<a href="../psi/gsos2.rc">psi/gsos2.rc</a>, -<a href="../base/gspmdrv.def">base/gspmdrv.def</a>, -<a href="../base/gspmdrv.icx">base/gspmdrv.icx</a>, -<a href="../base/gspmdrv.rc">base/gspmdrv.rc</a>, -<a href="../base/gswin.rc">base/gswin.rc</a>, -<a href="../base/gswin32.rc">base/gswin32.rc</a>, -<a href="../base/mv.bat">base/mv.bat</a>, -<a href="../base/mv.cmd">base/mv.cmd</a>, -<a href="../base/rm.bat">base/rm.bat</a>, -<a href="../base/rm.cmd">base/rm.cmd</a>, - -<dt> -Files for MacOS: -<dd> -<a href="../lib/Info-macos.plist">lib/Info-macos.plist</a>. - -<dt> -Files for OpenVMS: -<dd> -<a href="../base/append_l.com">base/append_l.com</a>, -<a href="../base/copy_one.com">base/copy_one.com</a>, -<a href="../base/rm_all.com">base/rm_all.com</a>, -<a href="../base/rm_one.com">base/rm_one.com</a>. - -<dt> -Other files: -<dd> -<a href="../base/bench.c">base/bench.c</a>, -<a href="../base/catmake">base/catmake</a>, -<a href="../base/instcopy">base/instcopy</a>. - -</dl> - -<h3><a name="Utilities"></a>Utilities</h3> - -<p> -Ghostscript comes with many utilities for doing things like viewing bitmap -files and converting between file formats. Some of these are written in -PostScript, some as scripts, and some as scripts that invoke special -PostScript code. - -<h4><a name="Utilities_in_PostScript"></a>Utilities in PostScript</h4> - -<p> -These are all documented in <a href="Psfiles.htm">doc/Psfiles.htm</a>, q.v. - -<h4><a name="Utility_scripts"></a>Utility scripts</h4> - -<p> -Many of these scripts come in both Unix and MS-DOS (<code>.bat</code> -versions; some also have an OS/2 (<code>.cmd</code>) version. The choice -of which versions are provided is historical and irregular. These scripts -should all be documented somewhere, but currently, many of them have man -pages, a few have their own documentation in the doc directory, and some -aren't documented at all. - -<dl> - -<dt> -Script files without PC versions: -<dd> -<a href="../lib/afmdiff.awk">lib/afmdiff.awk</a>, -<a href="../lib/dvipdf">lib/dvipdf</a>, -<a href="../lib/lprsetup.sh">lib/lprsetup.sh</a>, -<a href="../lib/pphs">lib/pphs</a>, -<a href="../lib/printafm">lib/printafm</a>, -<a href="../lib/unix-lpr.sh">lib/unix-lpr.sh</a>, -<a href="../lib/wftopfa">lib/wftopfa</a>. - -<dt> -Script files with PC versions: -<dd> -<a href="../lib/eps2eps">lib/eps2eps</a>, -<a href="../lib/eps2eps.bat">lib/eps2eps.bat</a>, -<a href="../lib/eps2eps.cmd">lib/eps2eps.cmd</a>, -<a href="../lib/ps2ps2">lib/ps2ps2</a>, -<a href="../lib/ps2ps2.bat">lib/ps2ps2.bat</a>, -<a href="../lib/ps2ps2.cmd">lib/ps2ps2.cmd</a>, -<a href="../lib/font2c">lib/font2c</a>, -<a href="../lib/font2c.bat">lib/font2c.bat</a>, -<a href="../lib/font2c.cmd">lib/font2c.cmd</a>, -<a href="../lib/gsbj">lib/gsbj</a>, -<a href="../lib/gsbj.bat">lib/gsbj.bat</a>, -<a href="../lib/gsdj">lib/gsdj</a>, -<a href="../lib/gsdj.bat">lib/gsdj.bat</a>, -<a href="../lib/gsdj500">lib/gsdj500</a>, -<a href="../lib/gsdj500.bat">lib/gsdj500.bat</a>, -<a href="../lib/gslj">lib/gslj</a>, -<a href="../lib/gslj.bat">lib/gslj.bat</a>, -<a href="../lib/gslp">lib/gslp</a>, -<a href="../lib/gslp.bat">lib/gslp.bat</a>, -<a href="../lib/gsnd">lib/gsnd</a>, -<a href="../lib/gsnd.bat">lib/gsnd.bat</a>, -<a href="../lib/pdf2dsc">lib/pdf2dsc</a>, -<a href="../lib/pdf2dsc.bat">lib/pdf2dsc.bat</a>, -<a href="../lib/pdf2ps">lib/pdf2ps</a>, -<a href="../lib/pdf2ps.bat">lib/pdf2ps.bat</a>, -<a href="../lib/pdf2ps.cmd">lib/pdf2ps.cmd</a>, -<a href="../lib/pf2afm">lib/pf2afm</a>, -<a href="../lib/pf2afm.bat">lib/pf2afm.bat</a>, -<a href="../lib/pf2afm.cmd">lib/pf2afm.cmd</a>, -<a href="../lib/pfbtopfa">lib/pfbtopfa</a>, -<a href="../lib/pfbtopfa.bat">lib/pfbtopfa.bat</a>, -<a href="../lib/ps2ascii">lib/ps2ascii</a>, -<a href="../lib/ps2ascii.bat">lib/ps2ascii.bat</a>, -<a href="../lib/ps2ascii.cmd">lib/ps2ascii.cmd</a>, -<a href="../lib/ps2epsi">lib/ps2epsi</a>, -<a href="../lib/ps2epsi.bat">lib/ps2epsi.bat</a>, -<a href="../lib/ps2epsi.cmd">lib/ps2epsi.cmd</a>, -<a href="../lib/ps2pdf">lib/ps2pdf</a>, -<a href="../lib/ps2pdf.bat">lib/ps2pdf.bat</a>, -<a href="../lib/ps2pdf.cmd">lib/ps2pdf.cmd</a>, -<a href="../lib/ps2pdf12">lib/ps2pdf12</a>, -<a href="../lib/ps2pdf12.bat">lib/ps2pdf12.bat</a>, -<a href="../lib/ps2pdf12.cmd">lib/ps2pdf12.cmd</a>, -<a href="../lib/ps2pdf13">lib/ps2pdf13</a>, -<a href="../lib/ps2pdf13.bat">lib/ps2pdf13.bat</a>, -<a href="../lib/ps2pdf13.cmd">lib/ps2pdf13.cmd</a>, -<a href="../lib/ps2pdf14">lib/ps2pdf14</a>, -<a href="../lib/ps2pdf14.bat">lib/ps2pdf14.bat</a>, -<a href="../lib/ps2pdf14.cmd">lib/ps2pdf14.cmd</a>, -<a href="../lib/ps2pdfwr">lib/ps2pdfwr</a>, -<a href="../lib/ps2pdfxx.bat">lib/ps2pdfxx.bat</a>, -<a href="../lib/ps2ps">lib/ps2ps</a>, -<a href="../lib/ps2ps.bat">lib/ps2ps.bat</a>, -<a href="../lib/ps2ps.cmd">lib/ps2ps.cmd</a>. - -<dt> -Script files with only PC versions: -<dd> -<a href="../lib/gsndt.bat">lib/gsndt.bat</a>, -<a href="../lib/gssetgs.bat">lib/gssetgs.bat</a>, -<a href="../lib/gssetgs32.bat">lib/gssetgs32.bat</a>, -<a href="../lib/gssetgs64.bat">lib/gssetgs64.bat</a>, -<a href="../lib/gst.bat">lib/gst.bat</a>, -<a href="../lib/gstt.bat">lib/gstt.bat</a>, -<a href="../lib/lp386.bat">lib/lp386.bat</a>, -<a href="../lib/lp386r2.bat">lib/lp386r2.bat</a>, -<a href="../lib/lpgs.bat">lib/lpgs.bat</a>, -<a href="../lib/lpr2.bat">lib/lpr2.bat</a>, -<a href="../lib/pftogsf.bat">lib/pftogsf.bat</a>, -<a href="../lib/wmakebat.bat">lib/wmakebat.bat</a>. - -</dl> - -<hr> - -<h2><a name="Memory_management"></a>Memory management</h2> - -<h3><a name="Memory_manager_architecture"></a>Memory manager architecture</h3> - -<p> -In many environments, the memory manager is a set of library facilities that -implicitly manage the entire address space in a homogenous manner. -Ghostscript's memory manager architecture has none of these properties: - -<ul> - -<li>Rather than a single library accessed as procedures, Ghostscript -includes multiple allocator types, each of which in turn may have multiple -instances (allocators). Allocators are 'objects' with a substantial set of -virtual functions. - -<li>Rather than managing the entire address space, each allocator manages a -storage pool, which it may or may not be able to expand or reduce by calling -on a 'parent' allocator. - -<li>Rather than a single genus of untyped storage blocks, Ghostscript's -allocators provide two genera -- type-tagged 'objects', and 'strings' -- -with substantially different properties. - -</ul> - -<h4><a name="Objects_vs_strings"></a>Objects vs strings</h4> - -<p> -As noted above, allocators provide two different storage genera. - -<p> -Objects: - -<ul> -<li>Are aligned in storage to satisfy the most stringent alignment -requirement imposed by the CPU or compiler; -<li>Can be referenced only by pointers to their start, not to any internal -location, unless special arrangements are made; -<li>May contain pointers to other objects, or to strings; -<li>Have an associated <em>structure descriptor</em> that specifies their -size (usually) and the location of any pointers contained within them. -</ul> - -<p> -Given a pointer to an object, the allocator that allocated it must be able -to return the object's size and the pointer to its structure descriptor. -(It is up to the client to know what allocator allocated an object.) - -<p> -Strings: - -<ul> -<li>Are not aligned in storage; -<li>Can be referenced by pointers (consisting of a starting address and a -length) to any substring, starting anywhere within the string; -<li>May not contain pointers; -<li>Do not have a structure descriptor. -</ul> - -<p> -The object/string distinction reflects a space/capability tradeoff. The -per-object space overhead of the standard type of allocator is typically 12 -bytes; this is too much to impose on every string of a few bytes. On the -other hand, restricting object pointers to reference the start of the object -currently makes object garbage collection and compaction more -space-efficient. If we were to redesign the standard allocator, we would -probably opt for a different design in which strings were allocated within -container objects of a few hundred bytes, and pointers into the middle of -all objects were allowed. - -<h4><a name="Structure_descriptors"></a>Structure descriptors</h4> - -<p> -Every object allocated by a Ghostscript allocator has an associated -structure descriptor, which the caller provides when allocating the object. -The structure descriptor serves several purposes: - -<ul> -<li>Specifying the size of the object for allocation; -<li>Providing pointer-enumeration and pointer-relocation procedures for -the garbage collector; -<li>Providing an optional finalization procedure to be called when the -object is freed (either explicitly or automatically). -</ul> - -<p> -Structure descriptors are read-only, and are normally defined statically -using one of the large set of <code>gs_private_st_</code> or -<code>gs_public_st_</code> macros in <a -href="../base/gsstruct.h">base/gsstruct.h</a>. - -<p> -While the structure descriptor normally specifies the size of the object, -one can also allocate an array of bytes or objects, whose size is a multiple -of the size in the descriptor. For this reason, every object stores its -size as well as a reference to its descriptor. - -<p> -Because the standard Ghostscript garbage collector is non-conservative and -can move objects, every object allocated by a Ghostscript allocator must -have an accurate structure descriptor. If you define a new type of object -(structure) that will be allocated in storage managed by Ghostscript, you -<em>must</em> create an accurate descriptor for it, and use that descriptor -to allocate it. The process of creating accurate descriptors for all -structures was long and painful, and accounted for many hard-to-diagnose -bugs. - -<p> -By convention, the structure descriptor for structure type -<code>xxx_t</code> is named <code>st_xxx</code> (this is preferred), -or occasionally <code>st_xxx_t</code>. - -<p> -Note that a structure descriptor is only required for objects allocated by -the Ghostscript allocator. A structure type <code>xxx_t</code> does not -require a structure descriptor if instances of that type are used -<em>only</em> in the following ways: - -<ul> - -<li>Instances are allocated only on the C stack, e.g., as -<code>xxx_t xxx1, xxx2;</code>, or on the C heap, with -<code>malloc</code> or through the Ghostscript "wrapper" defined in <a -href="../base/gsmalloc.h">base/gsmalloc.h</a>. - -<li>Pointers to instances are not stored in places where the garbage -collector will try to trace the pointer. - -<li>Code never attempts to get the structure type or size of an instance -through the allocator API. - -</ul> - -<p> -In general, structures without descriptors are problem-prone, and are -deprecated; in new code, they should only be used if the structure is -confined to a single .c file and its instances are only allocated on the C -stack. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsstruct.h">base/gsstruct.h</a>, -<a href="../base/gsstype.h">base/gsstype.h</a>. -</dl> - -<h4><a name="Garbage_collection"></a>Garbage collection</h4> - -<p> -The allocator architecture is designed to support compacting garbage -collection. Every object must be able to enumerate all the pointers it -contains, both for tracing and for relocation. As noted just above, the -structure descriptor provides procedures that do this. - -<p> -Whether or not a particular allocator type actually provides a garbage -collector is up to the allocator: garbage collection is invoked through a -virtual procedure. In practice, however, there are only two useful garbage -collectors for Ghostscript's own allocator: - -<ul> -<li>The "real" garbage collector associated with the PostScript interpreter, -described <a href="#Interpreter_GC">below</a>; -<li>A "non" garbage collector that only merges adjacent free blocks. -</ul> - -<p> -As noted above, because the architecture supports compacting garbage -collection, a "real" garbage collector cannot be run at arbitrary times, -because it cannot reliably find and relocate pointers that are on the C -stack. In general, it is only safe to run a "real" garbage collector when -control is at the top level of the program, when there are no pointers to -garbage collectable objects from the stack (other than designated roots). - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsgc.h">base/gsgc.h</a>, -<a href="../base/gsnogc.c">base/gsnogc.c</a>, -<a href="../base/gsnogc.h">base/gsnogc.h</a>. -</dl> - -<h4><a name="Movability"></a>Movability</h4> - -<p> -As just noted, objects are normally movable by the garbage collector. -However, some objects must be immovable, usually because some other piece of -software must retain pointers to them. The allocator API includes -procedures for allocating both movable (default) and immovable objects. -Note, however, that even immovable objects must be traceable (have a -structure descriptor), and may be freed, by the garbage collector. - -<h4><a name="Parent_hierarchy"></a>Parent hierarchy</h4> - -<p> -When an allocator needs to add memory to the pool that it manages, it -requests the memory from its <em>parent</em> allocator. Every allocator has -a pointer to its parent; multiple allocators may share a single parent. The -ultimate ancestor of all allocators that can expand their pool dynamically -is an allocator that calls <code>malloc</code>, described <a -href="#malloc">below</a>. However, especially in embedded environments, an -allocator may be limited to a fixed-size pool assigned to it when it is -created. - -<h4><a name="Allocator_API"></a>Allocator API</h4> - -In summary, the allocator API provides the following principal operations: - -<ul> -<li>Allocate and free movable (default) or immovable objects and strings. -<li>Return the structure type and size of an object. -<li>Resize (shrink or grow) movable objects and strings, preserving -the contents insofar as possible. -<li>Report the size of the managed pool, and how much of it is in use. -<li>Register and unregister root pointers for the garbage collector. -<li>Free the allocator itself. -<li>Consolidate adjacent free blocks to reduce fragmentation. -</ul> - -<p> -For details, see <a href="../base/gsmemory.h">base/gsmemory.h</a>. - -<p> -The allocator API also includes one special hook for the PostScript -interpreter: the concept of stable allocators. See the section on <a -href="#save_forgetsave_restore"><code>save</code> and -<code>restore</code></a> below for details. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsmemraw.h">base/gsmemraw.h</a>, -<a href="../base/gsmemory.c">base/gsmemory.c</a>, -<a href="../base/gsmemory.h">base/gsmemory.h</a>, -<a href="../base/gsstruct.h">base/gsstruct.h</a>, -<a href="../base/gsstype.h">base/gsstype.h</a>. -</dl> - -<h3><a name="Freeing_storage"></a>Freeing storage</h3> - -<p> -Ghostscript's memory management architecture provides three different ways -to free objects: explicitly, by reference counting, or by garbage -collection. They provide different safety / performance / convenience -tradeoffs; we believe that all three are necessary. - -<p> -Objects are always freed as a whole; strings may be freed piecemeal. - -<p> -An object may have an associated finalization procedure, defined in the -structure descriptor. This procedure is called just before the object is -freed, independent of which method is being used to free the object. A few -types of objects have a virtual finalization procedure as well: the -finalization procedure defined in the descriptor simply calls the one in the -object. - -<h4><a name="Explicit_freeing"></a>Explicit freeing</h4> - -<p> -Objects and strings may be freed explicitly, using the -<code>gs_free_</code> virtual procedures in the allocator API. It is up -to the client to ensure that all allocated objects are freed at most once, -and that there are no dangling pointers. - -<p> -Explicit freeing is the fastest method, but is the least convenient and -least safe. It is most appropriate when storage is freed in the same -procedure where it is allocated, or for storage that is known to be -referenced by only one pointer. - -<h4><a name="Reference_counting"></a>Reference counting</h4> - -<p> -Objects may be managed by reference counting. When an object is allocated, -its reference count may be set to 0 or 1. Subsequently, when the reference -count is decremented to 0, the object is freed. - -<p> -The reference counting machinery provides its own virtual finalization -procedure for all reference-counted objects. The machinery calls this -procedure when it is about to free the object (but not when the object is -freed in any other way, which is probably a design bug). This is in -addition to (and called before) any finalization procedure associated with -the object type. - -<p> -Reference counting is as fast as explicit freeing, but takes more space in -the object. It is most appropriate for relatively large objects which are -referenced only from a small set of pointers. Note that reference counting -cannot free objects that are involved in a pointer cycle (e.g., A -> B -> C --> A). - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsrefct.h">base/gsrefct.h</a>. -</dl> - -<h4><a name="Real_garbage_collection"></a>(Real) garbage collection</h4> - -<p> -Objects and strings may be freed automatically by a garbage collector. See -<a href="#Interpreter_GC">below</a>. - -<h3><a name="Special_implementations"></a>Special implementations</h3> - -<h4><a name="malloc"></a>malloc</h4> - -<p> -As mentioned <a href="#Parent_hierarchy">above</a>, the ultimate ancestor of -all allocators with an expandable pool is one that calls -<code>malloc</code>. - -<p>Note that the default gsmalloc.c allocator for malloc/free now uses -a mutex so that allocators that use this can be assured of thread safe -behavior. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsmalloc.h">base/gsmalloc.h</a>, -<a href="../base/gsmalloc.c">base/gsmalloc.c</a>. -</dl> - -<h4><a name="Locking"></a>Locking</h4> - -<p> -In a multi-threaded environment, if an allocator must be callable from -multiple threads (for example, if it is used to allocate structures in one -thread that are passed to, and freed by, another thread), the allocator must -provide mutex protection. Ghostscript provides this capability in the form -of a <em>wrapper</em> allocator, that simply forwards all calls to a -<em>target</em> allocator under protection of a mutex. Using the wrapper -technique, any allocator can be made thread-safe. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsmemlok.h">base/gsmemlok.h</a>, -<a href="../base/gsmemlok.c">base/gsmemlok.c</a>. -</dl> - -<h4><a name="Retrying"></a>Retrying</h4> - -<p> -In an embedded environment, job failure due to memory exhaustion is very -undesirable. Ghostscript provides a wrapper allocator that, when an -allocation attempt fails, calls a client-provided procedure that can attempt -to free memory, then ask for the original allocation to be retried. For -example, such a procedure can wait for a queue to empty, or can free memory -occupied by caches. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsmemret.h">base/gsmemret.h</a>, -<a href="../base/gsmemret.c">base/gsmemret.c</a>. -</dl> - -<h4><a name="Chunk"></a>Chunk</h4> - -<p>When multiple threads are used and there may be frequent memory allocator -requests, mutex contention is a problem and can cause severe performance -degradation. The chunk memory wrapper can provide each thread with its own -instance of an allocator that only makes requests on the underlying (non-GC) -alloctor when large blocks are needed. Small object allocations are managed -within chunks. - -<p>This allocator is intended to be used on top of the basic 'gsmalloc' -allocator (malloc/free) which is NOT garbage collected or relocated and -which MUST be mutex protected. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsmchunk.h">base/gsmchunk.h</a>, -<a href="../base/gsmchunk.c">base/gsmchunk.c</a>. -</dl> - -<h3><a name="Standard_implementation"></a>Standard implementation</h3> - -<p> -The standard Ghostscript allocator gets storage from its parent (normally -the <code>malloc</code> allocator) in large blocks called -<em>clumps</em>, and then allocates objects up from the low end and strings -down from the high end. Large objects or strings are allocated in their own -clump. - -<p> -The standard allocator maintains a set of free-block lists for small object -sizes, one list per size (rounded up to the word size), plus a free-block -list for large objects (but not for objects so large that they get their own -clump: when such an object is freed, its chunk is returned to the parent). -The lists are not sorted; adjacent blocks are only merged if needed. - -<p> -While the standard allocator implements the generic allocator API, and is -usable with the library alone, it includes a special hook for the PostScript -interpreter to aid in the efficient allocation of PostScript composite -objects (arrays and dictionaries). See the section on <a -href="#Refs">Refs</a> below for details. - -<dl> -<dt> -Files: -<dd> -<a href="../base/gsalloc.c">base/gsalloc.c</a>, -<a href="../base/gsalloc.h">base/gsalloc.h</a>, -<a href="../base/gxalloc.h">base/gxalloc.h</a>, -<a href="../base/gxobj.h">base/gxobj.h</a>. -</dl> - -<h3><a name="PostScript_interpreter_extensions"></a>PostScript interpreter extensions</h3> - -<p> -The PostScript interpreter uses an allocator that extends the graphic -library's standard allocator to handle PostScript objects, -<code>save</code> and <code>restore</code>, and real garbage -collection. - -<h4><a name="Refs"></a>Refs (PostScript "objects")</h4> - -<p> -Ghostscript represents what the PLRM calls PostScript "objects" using a -structure called a <code>ref</code>, defined in <a -href="../psi/iref.h">psi/iref.h</a>; packed refs, used for the elements of -packed arrays, are defined in <a href="../psi/ipacked.h">psi/ipacked.h</a>. -See those files for detailed information. - -<dl> -<dt> -Files: -<dd> -<a href="../psi/ipacked.h">psi/ipacked.h</a>, -<a href="../psi/iref.h">psi/iref.h</a>. -</dl> - -<p> -The PLRM calls for two types of "virtual memory" (VM) space: global and -local. Ghostscript adds a third space, <em>system</em> VM, whose lifetime -is an entire session -- i.e., it is effectively "permanent". All three -spaces are subject to garbage collection. There is a separate allocator -instance for each VM space (actually, two instances each for global and -local spaces; see <a href="#save_forgetsave_restore">below</a>). In a -system with multiple contexts and multiple global or local VMs, each global -or local VM has its own allocator instance(s). - -<p> -Refs that represent PostScript composite objects, and therefore include -pointers to stored data, include a 2-bit VM space tag to indicate in which -VM the object data are stored. In addition to system, global, and local VM, -there is a tag for "foreign" VM, which means that the memory is not managed -by a Ghostscript allocator at all. Every store into a composite object must -check for <code>invalidaccess</code>: the VM space tag values are chosen -to help make this check efficient. See <a -href="../psi/ivmspace.h">psi/ivmspace.h</a>, <a -href="../psi/iref.h">psi/iref.h</a>, and <a -href="../psi/store.h">psi/store.h</a> for details. - -<dl> -<dt> -Files: -<dd> -<a href="../psi/ivmspace.h">psi/ivmspace.h</a>. -</dl> - -<p> -PostScript composite objects (arrays and dictionaries) are usually small. -Using a separate memory manager object for each composite object would waste -a lot of space for object headers. Therefore, the interpreter's memory -manager packs multiple composite objects (also called "ref-containing -objects") into a single memory manager object, similar to the way the memory -manager packs multiple objects into a clump (see <a -href="#Standard_implementation">above</a>). See <a -href="../base/gxalloc.h">base/gxalloc.h</a> for details. This memory manager -object has a structure descriptor, like all other memory manager objects. - -<p> -Note that the <code>value.pdict</code>, <code>value.refs</code>, or -<code>value.packed</code> member of a ref must point to a PostScript -composite object, and therefore can point into the middle of a memory -manager object. This requires special handling by the garbage collector (<a -href="#Interpreter_GC">q.v.</a>). - -<dl> -<dt> -Files: -<dd> -<a href="../psi/ialloc.c">psi/ialloc.c</a>, -<a href="../psi/ialloc.h">psi/ialloc.h</a>, -<a href="../psi/iastate.h">psi/iastate.h</a>, -<a href="../psi/iastruct.h">psi/iastruct.h</a>, -<a href="../psi/ilocate.c">psi/ilocate.c</a>, -<a href="../psi/imemory.h">psi/imemory.h</a>, -<a href="../psi/istruct.h">psi/istruct.h</a>. -</dl> - -<h4><a name="save_forgetsave_restore"></a>save/.forgetsave/restore</h4> - -<p> -In addition to <code>save</code> and <code>restore</code>, Ghostscript -provides a <code>.forgetsave</code> operator that makes things as though -a given <code>save</code> had never happened. (In data base terminology, -<code>save</code> is "begin transaction", <code>restore</code> is -"abort transaction", and <code>.forgetsave</code> is "end/commit -transaction"). <code>.forgetsave</code> was implemented for a specific -commercial customer (who may no longer even be using it): it was a pain to -make work, but it's in the code now, and should be maintained. See the -extensive comments in <a href="../psi/isave.c">psi/isave.c</a> for more -information about how these operations work. - -<dl> -<dt> -Files: -<dd> -<a href="../psi/idosave.h">psi/idosave.h</a>, -<a href="../psi/isave.c">psi/isave.c</a>, -<a href="../psi/isave.h">psi/isave.h</a>, -<a href="../psi/isstate.h">psi/isstate.h</a>, -<a href="../psi/store.h">psi/store.h</a>. -</dl> - -<h4><a name="Stable_allocators"></a>Stable allocators</h4> - -<p> -Even though <code>save</code> and <code>restore</code> are concepts -from the PostScript interpreter, the generic allocator architecture and API -include a feature to support them, called <em>stable</em> allocators. Every -allocator has an associated stable allocator, which tags pointers with the -same VM space number but which is not subject to <code>save</code> and -<code>restore</code>. System VM is intrinsically stable (its associated -stable allocator is the same allocator), so there are only 5 allocators in -ordinary single-context usage: system VM, stable global VM, ordinary global -VM, stable local VM, ordinary local VM. - -<p> -The reason that we cannot simply allocate all stable objects in system VM is -that their refs must still be tagged with the correct VM space number, so -that the check against storing pointers from global VM to local VM can be -enforced properly. - -<p> -All PostScript objects are normally allocated with the non-stable -allocators. The stable allocators should be used with care, since using -them can easily create dangling pointers: if storage allocated with a stable -allocator contains any references to PostScript objects, the client is -responsible for ensuring that the references don't outlive the referenced -objects, normally by ensuring that any such referenced objects are allocated -at the outermost <code>save</code> level. - -<p> -The original reason for wanting stable allocators was the PostScript stacks, -which are essentially PostScript arrays but are not subject to -<code>save</code> and <code>restore</code>. Some other uses of stable -allocators are: - -<ul> - -<li>Several per-context structures for DPS. - -<li>Paths (see <code>gstate_path_memory</code> in -<a href="../base/gsstate.c">base/gsstate.c</a>. - -<li>Row buffers for images (see <code>gs_image_row_memory</code> in <a -href="../base/gsimage.c">base/gsimage.c</a>), because the data-reading -procedure for an image can invoke <code>save</code> and -<code>restore</code>. - -<li>Notification lists for fonts, to handle the sequence allocate .. save -.. register .. restore. - -<li>The parameter lists for pdfwrite and epswrite devices (in <a -href="../devices/vector/gdevpsdp.c">devices/vector/gdevpsdp.c</a>), because the whole issue of -local vs. global VM for setpagedevice is, in the words of Ed Taft of Adobe, -"a mess". - -<li>Many places in the pdfwrite driver, because many of its bookkeeping -structures must not be restorable. - -</ul> - -<p> -For more specific examples, search the sources for references to -<code>gs_memory_stable</code>. - -<h4><a name="Interpreter_GC"></a>Garbage collection</h4> - -<p> -The interpreter's garbage collector is a compacting, non-conservative, -mark-and-sweep collector. - -<ul> -<li>It compacts storage because that is the only way to avoid permanent -sandbars, which is essential in limited-memory environments. -<li>It is non-conservative because conservative collectors (which attempt -to determine whether arbitrary bit patterns are pointers) cannot compact. -<li>It uses mark-and-sweep, rather than a more modern copying approach, -because it cannot afford the extra memory required for copying. -</ul> - -<p> -Because the garbage collector is non-conservative, it cannot be run if there -are any pointers to movable storage from the C stack. Thus it cannot be run -automatically when the allocator is unable to allocate requested space. -Instead, when the allocator has allocated a given amount of storage (the -<code>vm_threshold</code> amount, corresponding to the PostScript -<code>VMThreshold</code> parameter), it sets a flag that the interpreter -checks in the main loop. When the interpreter sees that this flag is set, -it calls the garbage collector: at that point, there are no problematic -pointers from the stack. - -<p> -Roots for tracing must be registered with the allocator. Most roots are -registered during initialization. - -<p> -"Mark-and-sweep" is a bit of a misnomer. The garbage collector actually has -5 main phases: - -<ul> -<li>Sweep to clear marks; -<li>Trace and mark; -<li>Sweep to compute relocation; -<li>Sweep to relocate pointers; -<li>Sweep and compact. -</ul> - -<p> -There is some extra complexity to handle collecting local VM only. In this -case, all pointers in global VM are treated as roots, and global VM is not -compacted. - -<p> -As noted above, PostScript arrays and strings can have refs that point -within them (because of <code>getinterval</code>). Thus the garbage -collector must mark each element of an array, and even each byte of a -string, individually. Specifically, it marks objects, refs, and strings -using 3 different mechanisms: - -<ul> - -<li>Objects have a mark bit in their header: see -<a href="../base/gxobj.h">base/gxobj.h</a>, - -<li>Refs and packed refs have a reserved mark bit: see <a -href="../psi/iref.h">psi/iref.h</a> and <a -href="../psi/ipacked.h">psi/ipacked.h</a>. - -<li>Strings use a separate bit table, with one bit per string byte: see -<a href="../base/gxalloc.h">base/gxalloc.h</a>, - -</ul> - -<p> -Similarly, it records the relocation information for objects, refs, and -strings differently: - -<ul> - -<li>Objects record relocation in the object header. - -<li>Refs record relocation in unused fields of refs such as nulls that -don't use their <code>value</code> field. Every memory manager object -that stores ref-containing objects as described above has an extra, unused -ref at the end for this purpose. - -<li>Strings use a separate relocation table. - -</ul> - -<dl> -<dt> -Files: -<dd> -<a href="../psi/igc.c">psi/igc.c</a>, -<a href="../psi/igc.h">psi/igc.h</a>, -<a href="../psi/igcref.c">psi/igcref.c</a>, -<a href="../psi/igcstr.c">psi/igcstr.c</a>, -<a href="../psi/igcstr.h">psi/igcstr.h</a>, -<a href="../psi/ireclaim.c">psi/ireclaim.c</a>. -</dl> - -<hr> - -<h2><a name="Portability"></a>Portability</h2> - -<p> -One of Ghostscript's most important features is its great portability across -platforms (CPUs, operating systems, compilers, and build tools). The code -supports portability through two mechanisms: - -<ul> - -<li><a href="#Structural">Structural mechanisms</a> -- segregating -platform-dependent information into files in a particular way. - -<li><a href="#Coding">Coding standards</a> -- avoiding relying on byte -order, scalar size, and platform-specific compiler or library features. - -</ul> - -<h3><a name="Structural"></a>Structural</h3> - -<h4><a name="CPU_and_compiler"></a>CPU and compiler</h4> - -<p> -Ghostscript attempts to discover characteristics of the CPU and compiler -automatically during the build process, by compiling and then executing a -program called <code>genarch</code>. <code>genarch</code> generates a -file <code>obj/arch.h</code>, which almost all Ghostscript files then -include. This works well for things like word size, byte order, and -floating point representation, but it can't determine whether or not a -compiler supports a particular feature, because if a feature is absent, the -compilation may fail. - -<dl> -<dt> -Files: -<dd> -<a href="../base/genarch.c">base/genarch.c</a>, -<a href="../obj/arch.h">obj/arch.h</a>. -</dl> - -<h4><a name="Library_headers"></a>Library headers</h4> - -<p> -Despite the supposed standardization of ANSI C, platforms vary considerably -in where (and whether) they provide various standard library facilities. -Currently, Ghostscript's build process doesn't attempt to sort this out -automatically. Instead, for each library header file -<code><</code><em>xxx</em><code>.h></code> there is a -corresponding Ghostscript source file -<code>base/</code><em>xxx</em><code>_.h</code>, containing a set of -compile-time conditionals that attempt to select the correct platform header -file, or in some cases substitute Ghostscript's own code for a missing -facility. You may need to edit these files when moving to platforms with -unusually non-standard libraries. - -<dl> -<dt> -Files: -<dd> -<a href="../base/ctype_.h">base/ctype_.h</a>, -<a href="../base/dirent_.h">base/dirent_.h</a>, -<a href="../base/dos_.h">base/dos_.h</a>, -<a href="../base/errno_.h">base/errno_.h</a>, -<a href="../base/fcntl_.h">base/fcntl_.h</a>, -<a href="../base/jerror_.h">base/jerror_.h</a>, -<a href="../base/malloc_.h">base/malloc_.h</a>, -<a href="../base/math_.h">base/math_.h</a>, -<a href="../base/memory_.h">base/memory_.h</a>, -<a href="../base/pipe_.h">base/pipe_.h</a>, -<a href="../base/png_.h">base/png_.h</a>, -<a href="../base/setjmp_.h">base/setjmp_.h</a>, -<a href="../base/stat_.h">base/stat_.h</a>, -<a href="../base/stdint_.h">base/stdint_.h</a>, -<a href="../base/stdio_.h">base/stdio_.h</a>, -<a href="../base/string_.h">base/string_.h</a>, -<a href="../base/time_.h">base/time_.h</a>, -<a href="../base/unistd_.h">base/unistd_.h</a>, -<a href="../base/vmsmath.h">base/vmsmath.h</a>, -<a href="../base/windows_.h">base/windows_.h</a>, -<a href="../base/x_.h">base/x_.h</a>. -</dl> - -<p> -It has been suggested that the GNU <code>configure</code> scripts do the -above better, for Unix systems, than Ghostscript's current methods. While -this may be true, we have found <code>configure</code> scripts difficult -to write, understand, and maintain; and the <code>autoconf</code> tool -for generating <code>configure</code> scripts, which we found easy to -use, doesn't cover much of the ground that Ghostscript requires. - -<h4><a name="Cross_platform_APIs"></a>Cross-platform APIs</h4> - -<p> -For a few library facilities that are available on all platforms but are not -well standardized, or that may need to be changed for special environments, -Ghostscript defines its own APIs. It is an architectural property of -Ghostscript that the implementations of these APIs are the only .c files for -which the choice of platform (as opposed to choices of drivers or optional -features) determines whether they are compiled and linked into an -executable. - -<dl> - -<dt> -API: -<dd> -<a href="../base/gp.h">base/gp.h</a>, -<a href="../base/gpcheck.h">base/gpcheck.h</a>, -<a href="../base/gpgetenv.h">base/gpgetenv.h</a>, -<a href="../base/gpmisc.h">base/gpmisc.h</a>, -<a href="../base/gpsync.h">base/gpsync.h</a>. - -<dt> -Implementation files shared among multiple platforms: -<dd> -<a href="../base/gp_getnv.c">base/gp_getnv.c</a>, -<a href="../base/gp_mktmp.c">base/gp_mktmp.c</a>, -<a href="../base/gp_nsync.c">base/gp_nsync.c</a>, -<a href="../base/gp_paper.c">base/gp_paper.c</a>, -<a href="../base/gp_psync.c">base/gp_psync.c</a>, -<a href="../base/gp_strdl.c">base/gp_strdl.c</a>, -<a href="../base/gpmisc.c">base/gpmisc.c</a>. - -<dt> -Platform-specific implementation files: -<dd> -<a href="../base/gp_dosfe.c">base/gp_dosfe.c</a>, -<a href="../base/gp_dosfs.c">base/gp_dosfs.c</a>, -<a href="../base/gp_dvx.c">base/gp_dvx.c</a>, -<a href="../base/gp_msdos.c">base/gp_msdos.c</a>, -<a href="../base/gp_mshdl.c">base/gp_mshdl.c</a>, -<a href="../base/gp_mslib.c">base/gp_mslib.c</a>, -<a href="../base/gp_mswin.c">base/gp_mswin.c</a>, -<a href="../base/gp_mswin.h">base/gp_mswin.h</a>, -<a href="../base/gp_ntfs.c">base/gp_ntfs.c</a>, -<a href="../base/gp_os2.c">base/gp_os2.c</a>, -<a href="../base/gp_os2.h">base/gp_os2.h</a>, -<a href="../base/gp_os2fs.c">base/gp_os2fs.c</a>, -<a href="../base/gp_os9.c">base/gp_os9.c</a>, -<a href="../base/gp_stdia.c">base/gp_stdia.c</a>, -<a href="../base/gp_stdin.c">base/gp_stdin.c</a>, -<a href="../base/gp_unifn.c">base/gp_unifn.c</a>, -<a href="../base/gp_unifs.c">base/gp_unifs.c</a>, -<a href="../base/gp_unix.c">base/gp_unix.c</a>, -<a href="../base/gp_unix_cache.c">base/gp_unix_cache.c</a>, -<a href="../base/gp_upapr.c">base/gp_upapr.c</a>, -<a href="../base/gp_vms.c">base/gp_vms.c</a>, -<a href="../base/gp_wgetv.c">base/gp_wgetv.c</a>, -<a href="../base/gp_win32.c">base/gp_win32.c</a>, -<a href="../base/gp_wpapr.c">base/gp_wpapr.c</a>, -<a href="../base/gp_wsync.c">base/gp_wsync.c</a>, -<a href="../base/gs_dll_call.h">base/gs_dll_call.h</a>. - -</dl> - -<h4><a name="Makefiles"></a>Makefiles</h4> - -<p> -For information on the structure and conventions used within makefiles, see -the <a href="#Makefile_structure">Makefile structure</a> section above. - -<p> -Ghostscript's makefiles are structured very similarly to the cross-platform -library files. The great majority of the makefiles are portable across all -platforms and all versions of <code>make</code>. To achieve this, the -platform-independent makefiles must obey two constraints beyond those of the -POSIX <code>make</code> program: - -<ul> - -<li>No conditionals or <code>include</code>s are allowed. While most -<code>make</code> programs now provide some form of conditional execution -and some form of inclusion, there is no agreement on the syntax. -(Conditionals and includes are allowed in platform-dependent makefiles; in -fact, an inclusion facility is required.) - -<li>There must be a space on both sides of the : that separates the target -of a rule from its dependencies. This is required for compatibility with -the OpenVMS <code>MMS</code> and <code>MMK</code> programs. - -</ul> - -<p> -The top-level makefile for each platform (where "platform" includes the OS, -the compiler, and the flavor of <code>make</code>) contains all the build -options, plus <code>include</code>s for the generic makefiles and any -platform-dependent makefiles that are shared among multiple platforms. - -<p> -While most of the top-level makefiles build a PostScript and/or PDF -interpreter configuration, there are also a few makefiles that build a test -program that only uses the graphics library without any language -interpreter. Among other things, this can be helpful in verifying that no -accidental dependencies on the interpreter have crept into the library or -drivers. - -<p> -For families of similar platforms, the question arises whether to use -multiple top-level makefiles, or whether to use a single top-level makefile -that may require minor editing for some (or all) platforms. Ghostscript -currently uses the following top-level makefiles for building interpreter -configurations: - -<ul> - -<li>POSIX systems (inluding Linux and Unix): -<ul> -<li><a href="../configure.ac"configure.ac</a>, -GNU Autoconf source script for automatic build configuration. -<li><a href="../Makefile.in">Makefile.in</a>, -source for the top-level makefile used in the Autoconf build. -<li><a href="../base/unix-gcc.mak">base/unix-gcc.mak</a>, -for Unix with gcc. -<li><a href="../base/unixansi.mak">base/unixansi.mak</a>, -for Unix with an ANSI C compiler other than gcc. -</ul> - -<li>PC: -<ul> -<li><a href="../ghostscript.vcproj">ghostscript.vcproj</a>, -Visual Studio project file used to build Ghostscript. -<li><a href="../psi/msvc32.mak">psi/msvc32.mak</a>, -for MS Windows with Microsoft Visual C (MSVC). -<li><a href="../psi/os2.mak">psi/os2.mak</a>, -for MS-DOS or OS/2 GCC/EMX environment. -</ul> - -<li>Macintosh: -<ul> -<li><a href="../base/macosx.mak">base/macosx.mak</a>, -commandline makefile for MacOS X. -<li><a href="../base/macos-mcp.mak">base/macos-mcp.mak</a>, -dummy makefile to generate an xml project file for Metrowerks Codewarrior. -</ul> - - -<li>Other: -<ul> -<li><a href="../base/all-arch.mak">base/all-arch.mak</a>, -for building on many Unix systems in a networked test environment. -<li><a href="../base/openvms.mak">base/openvms.mak</a>, -for OpenVMS with Digital's CC compiler and the MMS build program. -<li><a href="../base/openvms.mmk">base/openvms.mmk</a>, -for OpenVMS with Digital's CC compiler and the MMK build program. -</ul> - -</ul> - -<p> -The following top-level makefiles build the library test program: - -<ul> -<li><a href="../base/ugcclib.mak">base/ugcclib.mak</a>, -on Unix with gcc. -<li><a href="../base/msvclib.mak">base/msvclib.mak</a>, -on MS Windows with MSVC. -</ul> - -<p> -The MSVC makefiles may require editing to select between different versions -of MSVC, since different versions may have slightly incompatible command -line switches or customary installation path names. The Unix makefiles -often require editing to deal with differing library path names and/or -library names. For details, see <a href="Make.htm#Unix_build">the Unix -section</a> of the documentation for building Ghostscript. - -<dl> - -<dt> -Library test program: -<dd> -<a href="../base/gslib.c">base/gslib.c</a>. - -<dt> -Platform-independent makefiles: -<dd> - -<dl> - -<dt> -Graphics library and support: -<dd> -<a href="../devices/contrib.mak">devices/contrib.mak</a>, -<a href="../devices/devs.mak">devices/devs.mak</a>, -<a href="../base/gs.mak">base/gs.mak</a>, -<a href="../base/lib.mak">base/lib.mak</a>, -<a href="../base/version.mak">base/version.mak</a>. - -<dt> -PostScript interpreter and fonts: -<dd> -<a href="../psi/int.mak">psi/int.mak</a>. - -<dt> -Third-party libraries: -<dd> -<a href="../base/expat.mak">base/expat.mak</a>, -<a href="../base/ijs.mak">base/ijs.mak</a>, -<a href="../base/jbig2.mak">base/jbig2.mak</a>, -<a href="../base/ldf_jb2.mak">base/ldf_jb2.mak</a>, -<a href="../base/lwf_jp2.mak">base/lwf_jp2.mak</a>, -<a href="../base/jpeg.mak">base/jpeg.mak</a>, -<a href="../base/png.mak">base/png.mak</a>, -<a href="../base/zlib.mak">base/zlib.mak</a>. -</dl> - -<dt> -Shared platform-dependent makefiles: -<dd> - -<dl> - -<dt> -Unix: -<dd> -<a href="../base/unix-aux.mak">base/unix-aux.mak</a>, -<a href="../base/unix-dll.mak">base/unix-dll.mak</a>, -<a href="../base/unix-end.mak">base/unix-end.mak</a>, -<a href="../base/unixhead.mak">base/unixhead.mak</a>, -<a href="../base/unixinst.mak">base/unixinst.mak</a>, -<a href="../base/unixlink.mak">base/unixlink.mak</a>. - -<dt> -Microsoft Windows and MS-DOS: -<dd> -<a href="../base/msvccmd.mak">base/msvccmd.mak</a>, -<a href="../base/msvctail.mak">base/msvctail.mak</a>, -<a href="../base/pcwin.mak">base/pcwin.mak</a>, -<a href="../psi/winint.mak">psi/winint.mak</a>, -<a href="../base/winlib.mak">base/winlib.mak</a>, -<a href="../base/winplat.mak">base/winplat.mak</a>. - -</dl> - -</dl> - -<h3><a name="Coding"></a>Coding</h3> - -<p> -Coding for portability requires avoiding both <em>explicit</em> -dependencies, such as platform-dependent <code>#ifdef</code>s, and -<em>implicit</em> dependencies, such as dependencies on byte order or the -size of the integral types. - -<h4><a name="Explicit_dependencies"></a>Explicit dependencies</h4> - -<p> -The platform-independent .c files never, ever, use <code>#ifdef</code> or -<code>#if</code> to select code for specific platforms. Instead, we -always try to characterize some abstract property that is being tested. For -example, rather than checking for macros that are defined on those specific -platforms that have 64-bit <code>long</code> values, we define a macro -<code>ARCH_SIZEOF_LONG</code> that can then be tested. Such macros are -always defined in a .h file, either automatically in <code>arch.h</code>, -or explicitly in a <em>xxx</em><code>_.h</code> file, as described in -earlier sections. - -<dl> -<dt> -Files: -<dd> -<a href="../base/std.h">base/std.h</a>, -<a href="../base/stdpn.h">base/stdpn.h</a>, -<a href="../base/stdpre.h">base/stdpre.h</a>. -</dl> - -<h4><a name="Implicit_dependencies"></a>Implicit dependencies</h4> - -<p> -The most common source of byte ordering dependencies is casting between -types (T1 *) and (T2 *) where T1 and T2 are numeric types that aren't merely -signed/unsigned variants of each other. To avoid this, the only casts -allowed in the code are between numeric types, from a pointer type to a long -integral type, and between pointer types. - -<p> -Ghostscript's code assumes the following about the sizes of various types: - -<dl> -<dt>char<dd>8 bits -<dt>short<dd>16 bits -<dt>int<dd>32 or 64 bits -<dt>long<dd>32 or 64 bits -<dt>float<dd>32 bits (may work with 64 bits) -<dt>double<dd>64 bits (may work with 128 bits) -</dl> - -<p> -The code does not assume that the <code>char</code> type is signed (or -unsigned); except for places where the value is always a literal string, or -for interfacing to library procedures, the code uses <code>byte</code> (a -Ghostscript synonym for <code>unsigned char</code>) almost everywhere. - -<p> -Pointers are signed on some platforms and unsigned on others. In the few -places in the memory manager where it's necessary to reliably order-compare -(as opposed to equality-compare) pointers that aren't known to point to the -same allocated block of memory, the code uses the -<code>PTR_</code><em>relation</em> macros rather than direct comparisons. - -<p> -See the files listed above for other situations where a macro provides -platform-independence or a workaround for bugs in specific compilers or -libraries (of which there are a distressing number). - -<h4><a name="Platform_specific_code"></a>Platform-specific code</h4> - -<p> -There are some features that are inherently platform-specific: - -<ul> - -<li>Microsoft Windows requires a lot of special top-level code, and also has -an installer and uninstaller. - -<li>OS/2 requires a little special code. - -<li>MacOS also requires special top-level code (now distributed with the -standard Ghostscript package). - -<li>All platforms supporting DLLs (currently all three of the above) share -some special top-level code. - -</ul> - -<dl> - -<dt> -MS Windows files: -<dd> -<a href="../psi/dpmain.c">psi/dpmain.c</a>, -<a href="../psi/dwdll.c">psi/dwdll.c</a>, -<a href="../psi/dwdll.h">psi/dwdll.h</a>, -<a href="../psi/dwimg.c">psi/dwimg.c</a>, -<a href="../psi/dwimg.h">psi/dwimg.h</a>, -<a href="../psi/dwmain.c">psi/dwmain.c</a>, -<a href="../psi/dwmainc.c">psi/dwmainc.c</a>, -<a href="../psi/dwnodll.c">psi/dwnodll.c</a>, -<a href="../psi/dwreg.c">psi/dwreg.c</a>, -<a href="../psi/dwreg.h">psi/dwreg.h</a>, -<a href="../psi/dwres.h">psi/dwres.h</a>, -<a href="../psi/dwtext.c">psi/dwtext.c</a>, -<a href="../psi/dwtext.h">psi/dwtext.h</a>, -<a href="../psi/dwtrace.c">psi/dwtrace.c</a>, -<a href="../psi/dwtrace.h">psi/dwtrace.h</a>, -<a href="../base/gp_msdll.c">base/gp_msdll.c</a>, -<a href="../base/gp_mspol.c">base/gp_mspol.c</a>, -<a href="../base/gp_msprn.c">base/gp_msprn.c</a>, -<a href="../base/gsdllwin.h">base/gsdllwin.h</a>. - -<dt> -OS/2 files: -<dd> -<a href="../base/gp_os2pr.c">base/gp_os2pr.c</a>, - -<dt> -Unix files: -<dd> -<a href="../psi/dxmain.c">psi/dxmain.c</a>, -<a href="../psi/dxmainc.c">psi/dxmainc.c</a>. - -<dt> -Macintosh files: -<dd> -<a href="../devices/gdevmac.c">devices/gdevmac.c</a>, -<a href="../devices/gdevmac.h">devices/gdevmac.h</a>, -<a href="../devices/gdevmacpictop.h">devices/gdevmacpictop.h</a>, -<a href="../devices/gdevmacttf.h">devices/gdevmacttf.h</a>, -<a href="../base/gp_mac.c">base/gp_mac.c</a>, -<a href="../base/gp_mac.h">base/gp_mac.h</a>, -<a href="../base/gp_macio.c">base/gp_macio.c</a>, -<a href="../base/gp_macpoll.c">base/gp_macpoll.c</a>, -<a href="../base/gsiomacres.c">base/gsiomacres.c</a>, -<a href="../base/macgenmcpxml.sh">base/macgenmcpxml.sh</a>, -<a href="../base/macsystypes.h">base/macsystypes.h</a>, -<a href="../base/macos_carbon_pre.h">base/macos_carbon_pre.h</a>, -<a href="../base/macos_carbon_d_pre.h">base/macos_carbon_d_pre.h</a>, -<a href="../base/macos_classic_d_pre.h">base/macos_classic_d_pre.h</a>, - -<a href="../psi/dmmain.c">psi/dmmain.c</a>, -<a href="../psi/dmmain.r">psi/dmmain.r</a>. - -<dt> -VMS files: -<dd> -<a href="../base/vms_x_fix.h">base/vms_x_fix.h</a>. - -<dt> -DLL files: -<dd> -<a href="../psi/gsdll.c">psi/gsdll.c</a>, -<a href="../base/gsdll.h">base/gsdll.h</a>, -<a href="../devices/gdevdsp.c">devices/gdevdsp.c</a>, -<a href="../devices/gdevdsp.h">devices/gdevdsp.h</a>, -<a href="../devices/gdevdsp2.h">devices/gdevdsp2.h</a>, -<a href="../psi/iapi.c">psi/iapi.c</a>, -<a href="../psi/iapi.h">psi/iapi.h</a>, -<a href="../psi/idisp.c">psi/idisp.c</a>, -<a href="../psi/idisp.h">psi/idisp.h</a>. -<p> -The new DLL interface (new as of 7.0) is especially useful with the -new display device, so it is included here. Both are due to Russell -Lang. - -</dl> - - -<hr> - -<h2><a name="Troubleshooting"></a>Troubleshooting</h2> - -<p> -The Ghostscript code has many tracing and debugging features that can be -enabled at run time using the <code>-Z</code> command line switch, if the -executable was compiled with <code>DEBUG</code> defined. One -particularly useful combination is <code>-Z@\?</code>, which fills free -memory blocks with a pattern and also turns on run-time memory consistency -checking. For more information, see <a -href="Use.htm#Debugging">doc/Use.htm#Debugging</a>; you can also search for -occurrences of <code>if_debug</code> or <code>gs_debug_c</code> in the -source code. Note that many of these features are in the graphics library -and do not require a PostScript interpreter. - -<p> -The code also contains many run-time procedures whose only purpose is to be -called from the debugger to print out various data structures, including all -the procedures in <a href="../psi/idebug.c">psi/idebug.c</a> (for the -PostScript interpreter) and the <code>debug_dump_</code> procedures in <a -href="../base/gsmisc.c">base/gsmisc.c</a>. - -<dl> -<dt> -Files: -<dd> -<a href="Use.htm#Debugging">doc/Use.htm#Debugging</a>, -<a href="../base/gdebug.h">base/gdebug.h</a>, -<a href="../base/gsmdebug.h">base/gsmdebug.h</a>, -<a href="../psi/idebug.h">psi/idebug.h</a>, -<a href="../psi/idebug.c">psi/idebug.c</a>. -</dl> - -<hr> - -<h2><a name="Profiling"></a>Profiling</h2> -<h3><a name="ProfilingMSVC6"></a>Profiling with Microsoft Developer Studio 6</h3> - -<p> -The Microsoft profiling tool is included into Microsoft Developer Studio 6 -Enterprise Edition only. Standard Edition and Professional Edition do not include it. - -<p> -Microsoft profiler tool requires the application to be linked with -a special linker option. To provide it you need the following change to -<code>gs/base/msvccmd.mak</code> : - -<blockquote><pre><code> - -*** SVN-GS\HEAD\gs\src\msvccmd.mak Tue Jan 9 21:41:07 2007 ---- gs\src\msvccmd.mak Mon May 7 11:29:35 2007 -*************** -*** 159,163 **** - # Note that it must be followed by a space. - CT=/Od /Fd$(GLOBJDIR) $(NULL) $(CDCC) $(CPCH) -! LCT=/DEBUG /INCREMENTAL:YES - COMPILE_FULL_OPTIMIZED= # no optimization when debugging - COMPILE_WITH_FRAMES= # no optimization when debugging ---- 159,164 ---- - # Note that it must be followed by a space. - CT=/Od /Fd$(GLOBJDIR) $(NULL) $(CDCC) $(CPCH) -! # LCT=/DEBUG /INCREMENTAL:YES -! LCT=/DEBUG /PROFILE - COMPILE_FULL_OPTIMIZED= # no optimization when debugging - COMPILE_WITH_FRAMES= # no optimization when debugging -*************** -*** 167,175 **** - !if $(DEBUGSYM)==0 - CT= -! LCT= - CMT=/MT - !else - CT=/Zi /Fd$(GLOBJDIR) $(NULL) -! LCT=/DEBUG - CMT=/MTd - !endif ---- 168,178 ---- - !if $(DEBUGSYM)==0 - CT= -! # LCT= -! LCT=/PROFILE - CMT=/MT - !else - CT=/Zi /Fd$(GLOBJDIR) $(NULL) -! # LCT=/DEBUG -! LCT=/DEBUG /PROFILE - CMT=/MTd - !endif - -</code></pre></blockquote> - -Note that any of debug and release build may be profiled. - -<p> -Mictosoft Profiler tool can't profile a dynamically loaded DLLs. -When building Ghostscript with makefiles you need to specify -<code>MAKEDLL=0</code> to <code>nmake</code> command line. - -<p> -The Integrated Development Environment of Microsoft Developer Studio 6 -cannot profile a makefile-based project. Therefore the profiling tool -to be started from command line. - -<p> -The profiling from command line is a 4 step procedure. -The following batch file provides a sample for it : - -<blockquote><pre><code> - -set DEVSTUDIO=G:\Program Files\Microsoft Visual Studio -set GS_HOME=..\..\gs-hdp -set GS_COMMAND_LINE=%GS_HOME%\bin\gswin32c.exe -I%GS_HOME%\lib;f:\afpl\fonts -r144 -dBATCH -dNOPAUSE -d/DEBUG attachment.pdf -set START_FUNCTION=_main -set Path=%DEVSTUDIO%\Common\MSDev98\Bin;%DEVSTUDIO%\VC98\Bin -PREP.EXE /OM /SF %START_FUNCTION% /FT %GS_HOME%\bin\gswin32c.exe -If ERRORLEVEL 1 echo step 1 fails&exit -PROFILE /I %GS_HOME%\bin\gswin32c.pbi %GS_COMMAND_LINE% -If ERRORLEVEL 1 echo step 2 fails&exit -PREP /M %GS_HOME%\bin\gswin32c /OT xxx.pbt -If ERRORLEVEL 1 echo step 3 fails&exit -PLIST /ST xxx.pbt >profile.txt -If ERRORLEVEL 1 echo step 4 fails&exit - -</code></pre></blockquote> - -<p> -This batch file to be adopted to your configuration : - -<ul> -<li> -Edit the path to developer studio in the line 1. -<li> -Edit the Ghostscript home directory in the line 2. -<li> -Edit Ghostscript command line in line 3. Note that profiling without /NOPAUSE is a bad idea. -<li> -In the line 4 edit the function name to start the profiling from. -The sample code specifies _main as the starting function. -Note it is the linker's function name, which starts with underscore. -<li> -Edit the output file name in the line 5. -</ul> - - - - -<!-- [2.0 end contents] ==================================================== --> - -<!-- [3.0 begin visible trailer] =========================================== --> -<hr> - -<p> -<small>Copyright © 2001-2022 Artifex Software, Inc. All rights -reserved.</small> - -<p> -This software is provided AS-IS with no warranty, either express or -implied. - -This software is distributed under license and may not be copied, modified -or distributed except as expressly authorized under the terms of that -license. Refer to licensing information at <a href="https://www.artifex.com">https://www.artifex.com</a> -or contact Artifex Software, Inc., 1305 Grant Avenue - Suite 200, -Novato, CA 94945, U.S.A., +1(415)492-9861, for further information. - -<p> -<small>Ghostscript version 10.00.0, 7 September 2022 - -<!-- [3.0 end visible trailer] ============================================= --> - - -<!--FINISH EDITING HERE--> - </div><!-- close inner --> - </div><!-- close outer --> - </article> - </main> - <script src="site.js"></script> -</body> -</html> |