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diff --git a/man/TIFFRGBAImage.3t b/man/TIFFRGBAImage.3t new file mode 100644 index 00000000..1a7090c7 --- /dev/null +++ b/man/TIFFRGBAImage.3t @@ -0,0 +1,275 @@ +.\" $Header: /usr/people/sam/tiff/man/RCS/TIFFRGBAImage.3t,v 1.1 1995/10/11 22:53:37 sam Exp $ +.\" +.\" Copyright (c) 1991-1995 Sam Leffler +.\" Copyright (c) 1991-1995 Silicon Graphics, Inc. +.\" +.\" Permission to use, copy, modify, distribute, and sell this software and +.\" its documentation for any purpose is hereby granted without fee, provided +.\" that (i) the above copyright notices and this permission notice appear in +.\" all copies of the software and related documentation, and (ii) the names of +.\" Sam Leffler and Silicon Graphics may not be used in any advertising or +.\" publicity relating to the software without the specific, prior written +.\" permission of Sam Leffler and Silicon Graphics. +.\" +.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, +.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY +.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. +.\" +.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR +.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, +.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, +.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF +.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE +.\" OF THIS SOFTWARE. +.\" +.if n .po 0 +.TH TIFFRGBAImage 3T "October 15, 1995" +.SH NAME +TIFFRGBAImage \- read and decode an image into a raster +.SH SYNOPSIS +.nf +.B "#include <tiffio.h>" +.B "typedef unsigned char TIFFRGBValue;" +.B "typedef struct _TIFFRGBAImage TIFFRGBAImage;" +.B "int TIFFRGBAImageOK(TIFF* tif, char emsg[1024]);" +.B "int TIFFRGBAImageBegin(TIFFRGBAImage* img, TIFF* tif, int stopOnError, char emsg[1024]);" +.B "int TIFFRGBAImageGet(TIFFRGBAImage* img, uint32* raster, uint32 width, uint32 height);" +.B "void TIFFRGBAImageEnd(TIFFRGBAImage* img);" +.SH DESCRIPTION +The routines described here provide a high-level interface +through which +.SM TIFF +images may be read into memory. +Images may be strip- or tile-based and have a variety of different +characteristics: bits/sample, samples/pixel, photometric, etc. +Decoding state is encapsulated in a +.I TIFFRGBAImage +structure making it possible to capture state for multiple images +and quickly switch between them. +The target raster format can be customized to a particular application's +needs by installing custom routines that manipulate image data +according to application requirements. +.PP +The default usage for these routines is: check if an image can +be processed using +.IR TIFFRGBAImageOK , +construct a decoder state block using +.IR TIFFRGBAImageBegin , +read and decode an image into a target raster using +.IR TIFFRGBAImageGet , +and then +release resources using +.IR TIFFRGBAImageEnd . +.I TIFFRGBAImageGet +can be called multiple times to decode an image using different +state parameters. +If multiple images are to be displayed and there is not enough +space for each of the decoded rasters, multiple state blocks can +be managed and then calls can be made to +.I TIFFRGBAImageGet +as needed to display an image. +.PP +The generated raster is assumed to be an array of +.I width +times +.I height +32-bit entries, where +.I width +must be less than or equal to the width of the image (\c +.I height +may be any non-zero size). +If the raster dimensions are smaller than the image, the image data +is cropped to the raster bounds. +If the raster height is greater than that of the image, then the +image data are placed in the lower part of the raster. +(Note that the raster is assume to be organized such that the pixel +at location (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP]; +with the raster origin in the lower-left hand corner.) +.PP +Raster pixels are 8-bit packed red, green, blue, alpha samples. +The macros +.IR TIFFGetR , +.IR TIFFGetG , +.IR TIFFGetB , +and +.I TIFFGetA +should be used to access individual samples. +Images without Associated Alpha matting information have a constant +Alpha of 1.0 (255). +.PP +.I TIFFRGBAImageGet +converts non-8-bit images by scaling sample values. +Palette, grayscale, bilevel, +.SM CMYK\c +, and YCbCr images are converted to +.SM RGB +transparently. +Raster pixels are returned uncorrected by any colorimetry information +present in the directory. +.PP +The paramater +.I stopOnError +specifies how to act if an error is encountered while reading +the image. +If +.I stopOnError +is non-zero, then an error will terminate the operation; otherwise +.I TIFFRGBAImageGet +will continue processing data until all the possible data in the +image have been requested. +.SH "ALTERNATE RASTER FORMATS" +To use the core support for reading and processing +.SM TIFF +images, but write the resulting raster data in a different format +one need only override the ``\fIput methods\fP'' used to store raster data. +These methods are are defined in the +.I TIFFRGBAImage +structure and initially setup by +.I TIFFRGBAImageBegin +to point to routines that pack raster data in the default +.SM ABGR +pixel format. +Two different routines are used according to the physical organization +of the image data in the file: +.IR PlanarConfiguration =1 +(packed samples), +and +.IR PlanarConfiguration =2 +(separated samples). +Note that this mechanism can be used to transform the data before +storing it in the raster. +For example one can convert data +to colormap indices for display on a colormap display. +.SH "SIMULTANEOUS RASTER STORE AND DISPLAY" +It is simple to display an image as it is being read into memory +by overriding the put methods as described above for supporting +alternate raster formats. +Simply keep a reference to the default put methods setup by +.I TIFFRGBAImageBegin +and then invoke them before or after each display operation. +For example, the +.IR tiffgt (1) +utility uses the following put method to update the display as +the raster is being filled: +.sp +.nf +.ft C +static void +putContigAndDraw(TIFFRGBAImage* img, uint32* raster, + uint32 x, uint32 y, uint32 w, uint32 h, + int32 fromskew, int32 toskew, + unsigned char* cp) +{ + (*putContig)(img, raster, x, y, w, h, fromskew, toskew, cp); + if (x+w == width) { + w = width; + if (img->orientation == ORIENTATION_TOPLEFT) + lrectwrite(0, y-(h-1), w-1, y, raster-x-(h-1)*w); + else + lrectwrite(0, y, w-1, y+h-1, raster); + } +} +.ft R +.fi +.sp +(the original routine provided by the library is saved in the +variable +.IR putContig .) +.SH "SUPPORTING ADDITIONAL TIFF FORMATS" +The +.I TIFFRGBAImage +routines support the most commonly encountered flavors of +.SM TIFF. +It is possible to extend this support by overriding the ``\fIget method\fP'' +invoked by +.I TIFFRGBAImageGet +to read +.SM TIFF +image data. +Details of doing this are a bit involved, it is best to make a copy +of an existing get method and modify it to suit the needs of an +application. +.SH NOTES +Samples must be either 1, 2, 4, 8, or 16 bits. +Colorimetric samples/pixel must be either 1, 3, or 4 (i.e. +.I SamplesPerPixel +minus +.IR ExtraSamples ). +.PP +Palettte image colormaps that appear to be incorrectly written +as 8-bit values are automatically scaled to 16-bits. +.SH "RETURN VALUES" +All routines return +1 if the operation was successful. +Otherwise, 0 is returned if an error was encountered and +.I stopOnError +is zero. +.SH DIAGNOSTICS +All error messages are directed to the +.IR TIFFError (3T) +routine. +.PP +.BR "Sorry, can not handle %d-bit pictures" . +The image had +.I BitsPerSample +other than 1, 2, 4, 8, or 16. +.PP +.BR "Sorry, can not handle %d-channel images" . +The image had +.I SamplesPerPixel +other than 1, 3, or 4. +.PP +\fBMissing needed "PhotometricInterpretation" tag\fP. +The image did not have a tag that describes how to display +the data. +.PP +\fBNo "PhotometricInterpretation" tag, assuming RGB\fP. +The image was missing a tag that describes how to display it, +but because it has 3 or 4 samples/pixel, it is assumed to be +.SM RGB. +.PP +\fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP. +The image was missing a tag that describes how to display it, +but because it has 1 sample/pixel, it is assumed to be a grayscale +or bilevel image. +.PP +.BR "No space for photometric conversion table" . +There was insufficient memory for a table used to convert +image samples to 8-bit +.SM RGB. +.PP +\fBMissing required "Colormap" tag\fP. +A Palette image did not have a required +.I Colormap +tag. +.PP +.BR "No space for tile buffer" . +There was insufficient memory to allocate an i/o buffer. +.PP +.BR "No space for strip buffer" . +There was insufficient memory to allocate an i/o buffer. +.PP +.BR "Can not handle format" . +The image has a format (combination of +.IR BitsPerSample , +.IR SamplesPerPixel , +and +.IR PhotometricInterpretation ) +that can not be handled. +.PP +.BR "No space for B&W mapping table" . +There was insufficient memory to allocate a table used to map +grayscale data to +.SM RGB. +.PP +.BR "No space for Palette mapping table" . +There was insufficient memory to allocate a table used to map +data to 8-bit +.SM RGB. +.SH BUGS +Orientations other than bottom-left, or top-left are +not handled correctly. +.SH "SEE ALSO" +.IR libtiff (3T), +.IR TIFFOpen (3T), +.IR TIFFReadRGBAImage (3T) |