path: root/base/gstrans.h

/* Copyright (C) 2001-2023 Artifex Software, Inc.
   All Rights Reserved.

   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 the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/


/* Transparency definitions and interface */

#ifndef gstrans_INCLUDED
#  define gstrans_INCLUDED

#include "gstparam.h"
#include "gxcomp.h"
#include "gsmatrix.h"
#include "gxblend.h"
#include "gdevp14.h"
#include "gsfunc.h"

/*
 * Define the operations for the PDF 1.4 transparency compositor.
 */
typedef enum {
    PDF14_PUSH_DEVICE,
    PDF14_POP_DEVICE,
    PDF14_ABORT_DEVICE,
    PDF14_BEGIN_TRANS_GROUP,
    PDF14_END_TRANS_GROUP,
    PDF14_BEGIN_TRANS_PAGE_GROUP,
    PDF14_BEGIN_TRANS_TEXT_GROUP,
    PDF14_END_TRANS_TEXT_GROUP,
    PDF14_BEGIN_TRANS_MASK,
    PDF14_END_TRANS_MASK,
    PDF14_SET_BLEND_PARAMS,
    PDF14_PUSH_TRANS_STATE,
    PDF14_POP_TRANS_STATE,
    PDF14_PUSH_SMASK_COLOR,
    PDF14_POP_SMASK_COLOR
} pdf14_compositor_operations;

#define PDF14_OPCODE_NAMES \
{\
    "PDF14_PUSH_DEVICE      ",\
    "PDF14_POP_DEVICE       ",\
    "PDF14_ABORT_DEVICE     ",\
    "PDF14_BEGIN_TRANS_GROUP",\
    "PDF14_END_TRANS_GROUP  ",\
    "PDF14_BEGIN_TRANS_PAGE_GROUP",\
    "PDF14_BEGIN_TRANS_TEXT_GROUP  ",\
    "PDF14_END_TRANS_TEXT_GROUP  ",\
    "PDF14_BEGIN_TRANS_MASK ",\
    "PDF14_END_TRANS_MASK   ",\
    "PDF14_SET_BLEND_PARAMS ",\
    "PDF14_PUSH_TRANS_STATE ",\
    "PDF14_POP_TRANS_STATE  ",\
    "PDF14_PUSH_SMASK_COLOR ",\
    "PDF14_POP_SMASK_COLOR  "\
}

/* Bit definitions for serializing PDF 1.4 parameters */
#define PDF14_SET_BLEND_MODE    (1 << 0)
#define PDF14_SET_TEXT_KNOCKOUT (1 << 1)
#define PDF14_SET_AIS   (1 << 2)
#define PDF14_SET_OVERPRINT		(1 << 4)
#define PDF14_SET_FILLCONSTANTALPHA (1 << 6)
#define PDF14_SET_STROKECONSTANTALPHA (1 << 7)
#define PDF14_SET_STROKEOVERPRINT (1 << 8)
#define PDF14_SET_FILLSTROKE_STATE (1 << 9)

/* Used for keeping track of the text group madness, since we have the pdf14
   device needs to know if we are int an BT/ET group vs. a FreeText Annotation
   as well as if we have already pushed a special knockout non-isolated group
   for doing text knockout */
typedef enum {
    PDF14_TEXTGROUP_NO_BT,  /* We are not in a BT/ET.  Avoids Annotation Texts */
    PDF14_TEXTGROUP_BT_NOT_PUSHED, /* We are in a BT/ET but no group pushed */
    PDF14_TEXTGROUP_BT_PUSHED,   /* We are in a BT/ET section and group was pushed */
    PDF14_TEXTGROUP_MISSING_ET   /* We pushed a group already and then had another BT occur */
} pdf14_text_group_state;

struct gs_pdf14trans_params_s {
    /* The type of trasnparency operation */
    pdf14_compositor_operations pdf14_op;
    int num_spot_colors;    /* Only for devices which support spot colors. */
    int num_spot_colors_int; /* Number of spot colors reported by the interpreter */
    bool overprint_sim_push; /* If true, put_image will need special conversion */
    /* Changed parameters flag */
    int changed;
    /* Parameters from the gs_transparency_group_params_t structure */
    bool Isolated;
    bool Knockout;
    bool image_with_SMask;
    gs_rect bbox;
    /*The transparency channel selector */
    gs_transparency_channel_selector_t csel;
    /* Parameters from the gx_transparency_mask_params_t structure */
    gs_transparency_mask_subtype_t subtype;
    bool function_is_identity;
    int Background_components;
    float Background[GS_CLIENT_COLOR_MAX_COMPONENTS];
    const gs_color_space *ColorSpace;
    int Matte_components;
    float Matte[GS_CLIENT_COLOR_MAX_COMPONENTS];
    float GrayBackground;  /* This is used to determine if the
                              softmask's bbox needs to be adjusted
                              to the parent groups bbox.  Since
                              the soft mask can affect areas
                              outside its own groups bounding
                              box in such a case */
    gs_function_t *transfer_function;
    byte transfer_fn[MASK_TRANSFER_FUNCTION_SIZE*2+2];
    /* Individual transparency parameters */
    gs_blend_mode_t blend_mode;
    bool text_knockout;
    int text_group;
    bool page_group;
    bool ais;
    bool shade_group;
    float opacity;
    float shape;
    float fillconstantalpha;
    float strokeconstantalpha;
    bool mask_is_image;
    gs_matrix ctm;
    bool replacing;
    bool overprint;
    bool stroke_overprint;
    bool effective_overprint_mode;
    bool stroke_effective_op_mode;
    bool idle; /* For clist reader.*/
    uint mask_id; /* For clist reader.*/
    int group_color_numcomps;
    gs_transparency_color_t group_color_type;
    int64_t icc_hash;
    cmm_profile_t *iccprofile;               /* The profile  */
    bool crop_blend_params;  /* This is used when the blend params are updated
                                during a transparency group push */
    bool is_pattern;      /* Needed to detect device push and pop for clist pattern */
    PDF14_OP_FS_STATE op_fs_state;
};

/*
 * The PDF 1.4 transparency compositor structure. This is exactly analogous to
 * other compositor structures, consisting of a the compositor common elements
 * and the PDF 1.4 transparency specific parameters.
 */
typedef struct gs_pdf14trans_s {
    gs_composite_common;
    gs_pdf14trans_params_t  params;
} gs_pdf14trans_t;

/* Access transparency-related graphics state elements. */
int gs_setblendmode(gs_gstate *, gs_blend_mode_t);
gs_blend_mode_t gs_currentblendmode(const gs_gstate *);
int gs_settextknockout(gs_gstate *, bool);
bool gs_currenttextknockout(const gs_gstate *);

/*
 * We have to abbreviate the procedure name because procedure names are
 * only unique to 23 characters on VMS.
 */
/* For the push_pdf14trans_device, depth is a estimate (not authoritative) of
 * the transparency stack depth. Value 0 means "unknown". If the depth value
 * is < 0, that means that this pdf14 device is being used for the overprint
 * simulation, and ordiniarly the value will be -1, since overprint
 * simulation only needs the page buffer.
 * The spot_color_count is provided for PDF input files to define the number
 * of Spot colorants beyond CMYK. Thus 0 means CMYK only. If unknown, such
 * as with PostScript input, the value will be -1.
 */
int gs_push_pdf14trans_device(gs_gstate * pgs, bool is_pattern, bool retain,
                              int depth, int spot_color_count);

int gs_pop_pdf14trans_device(gs_gstate * pgs, bool is_pattern);

int gs_abort_pdf14trans_device(gs_gstate * pgs);

void gs_trans_group_params_init(gs_transparency_group_params_t *ptgp, float opacity);

int gs_update_trans_marking_params(gs_gstate * pgs);

int gs_begin_transparency_group(gs_gstate * pgs,
                                const gs_transparency_group_params_t *ptgp,
                                const gs_rect *pbbox, pdf14_compositor_operations group_type);

int gs_end_transparency_group(gs_gstate *pgs);

int gs_end_transparency_text_group(gs_gstate *pgs);
int gs_begin_transparency_text_group(gs_gstate *pgs);

void gs_trans_mask_params_init(gs_transparency_mask_params_t *ptmp,
                               gs_transparency_mask_subtype_t subtype);

int gs_begin_transparency_mask(gs_gstate *pgs,
                               const gs_transparency_mask_params_t *ptmp,
                               const gs_rect *pbbox, bool mask_is_image);

int gs_end_transparency_mask(gs_gstate *pgs,
                             gs_transparency_channel_selector_t csel);

/*
 * Imager level routines for the PDF 1.4 transparency operations.
 */
int gx_begin_transparency_group(gs_gstate * pgs, gx_device * pdev,
                                const gs_pdf14trans_params_t * pparams);

int gx_end_transparency_group(gs_gstate * pgs, gx_device * pdev);

int gx_begin_transparency_mask(gs_gstate * pgs, gx_device * pdev,
                                const gs_pdf14trans_params_t * pparams);

int gx_end_transparency_mask(gs_gstate * pgs, gx_device * pdev,
                                const gs_pdf14trans_params_t * pparams);

int gx_abort_trans_device(gs_gstate * pgs, gx_device * pdev);


/* These are used for watching for q Smask Q events.  We need to
   send special compositor commands to keep the bands in sync
   with the current softmask during clist rendering.  Like the
   other transparency operations the gs functions occur on the
   clist writer side and the gx functions occur on the
   clist reader side */

int gs_push_transparency_state(gs_gstate *pgs);

int gs_pop_transparency_state(gs_gstate *pgs, bool force);

int gx_push_transparency_state(gs_gstate * pgs, gx_device * pdev);

int gx_pop_transparency_state(gs_gstate * pgs, gx_device * pdev);

/*
 * Verify that a compositor data structure is for the PDF 1.4 compositor.
 */
int gs_is_pdf14trans_compositor(const gs_composite_t * pct);

int gs_setstrokeconstantalpha(gs_gstate *pgs, float alpha);
float gs_getstrokeconstantalpha(const gs_gstate *pgs);
int gs_setfillconstantalpha(gs_gstate *pgs, float alpha);
float gs_getfillconstantalpha(const gs_gstate *pgs);
int gs_setalphaisshape(gs_gstate *pgs, bool AIS);
bool gs_getalphaisshape(gs_gstate *pgs);

/*
 * Estimate the amount of space that will be required by the PDF 1.4
 * transparency buffers for doing the blending operations.  These buffers
 * use 8 bits per component plus one or two 8 bit alpha component values.
 * In theory there can be a large number of these buffers required.  However
 * we do not know the required number of buffers, the required numbe of
 * alpha chanels, or the number of components for the blending operations.
 * (This information is determined later as the data streams are parsed.)
 * For now we are simply assuming that we will have three buffers with five
 * eight bit values.  This is a hack but not too unreasonable.  However
 * since it is a hack, we may exceed our desired buffer space while
 * processing the file.
 */
#define NUM_PDF14_BUFFERS 4     /* totally a random guess */
#define NUM_ALPHA_CHANNELS 1    /* common, but doesn't include possible tag, shape or group alpha */
#define NUM_COLOR_CHANNELS 4    /* CMYK is most common 'worst case' */
/* The estimated size of an individual PDF 1.4 buffer row (in bits) */
#define ESTIMATED_PDF14_ROW_SIZE(width, target_num_components, bits) ((width) * (bits)\
        * (NUM_ALPHA_CHANNELS + max(target_num_components,NUM_COLOR_CHANNELS)))
/* The estimated size of one row in all PDF 1.4 buffers (in bits) */
#define ESTIMATED_PDF14_ROW_SPACE(width, target_num_components, bits) \
        (NUM_PDF14_BUFFERS * ESTIMATED_PDF14_ROW_SIZE(width, target_num_components, bits))

#endif /* gstrans_INCLUDED */