harvey/sys/src/cmd/gs/src/gscolor.c

/* Copyright (C) 1989, 1992, 1993, 1994, 1996, 1997, 1998, 1999 Aladdin Enterprises.  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.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gscolor.c,v 1.14 2004/08/04 19:36:12 stefan Exp $ */
/* Color and halftone operators for Ghostscript library */
#include "gx.h"
#include "gserrors.h"
#include "gsstruct.h"
#include "gsutil.h"		/* for gs_next_ids */
#include "gsccolor.h"
#include "gxcspace.h"
#include "gxdcconv.h"
#include "gxdevice.h"		/* for gx_color_index */
#include "gxcmap.h"
#include "gscolor2.h"
#include "gzstate.h"

/* Imported from gsht.c */
void gx_set_effective_transfer(gs_state *);

/* Structure descriptors */
public_st_client_color();
public_st_transfer_map();

/* GC procedures */
private 
ENUM_PTRS_WITH(transfer_map_enum_ptrs, gx_transfer_map *mptr) return 0;
case 0: ENUM_RETURN((mptr->proc == 0 ? mptr->closure.data : 0));
ENUM_PTRS_END
private RELOC_PTRS_WITH(transfer_map_reloc_ptrs, gx_transfer_map *mptr)
{
    if (mptr->proc == 0)
	RELOC_PTR(gx_transfer_map, closure.data);
}
RELOC_PTRS_END

/* Initialize colors with 1, or 3, or 4 paint components. */
/* (These are only used by setcolorspace.) */
void
gx_init_paint_1(gs_client_color * pcc, const gs_color_space * pcs)
{
    pcc->paint.values[0] = 0.0;
}
void
gx_init_paint_3(gs_client_color * pcc, const gs_color_space * pcs)
{
    pcc->paint.values[2] = 0.0;
    pcc->paint.values[1] = 0.0;
    pcc->paint.values[0] = 0.0;
}
void
gx_init_paint_4(gs_client_color * pcc, const gs_color_space * pcs)
{
    /* DeviceCMYK and CIEBasedDEFG spaces initialize to 0,0,0,1. */
    pcc->paint.values[3] = 1.0;
    gx_init_paint_3(pcc, pcs);
}

/* Force a value into the range [0.0..1.0]. */
#define FORCE_UNIT(p) (p <= 0.0 ? 0.0 : p >= 1.0 ? 1.0 : p)

/* Restrict colors with 1, 3, or 4 components to the range (0,1). */
void
gx_restrict01_paint_1(gs_client_color * pcc, const gs_color_space * pcs)
{
    pcc->paint.values[0] = FORCE_UNIT(pcc->paint.values[0]);
}
void
gx_restrict01_paint_3(gs_client_color * pcc, const gs_color_space * pcs)
{
    pcc->paint.values[2] = FORCE_UNIT(pcc->paint.values[2]);
    pcc->paint.values[1] = FORCE_UNIT(pcc->paint.values[1]);
    pcc->paint.values[0] = FORCE_UNIT(pcc->paint.values[0]);
}
void
gx_restrict01_paint_4(gs_client_color * pcc, const gs_color_space * pcs)
{
    pcc->paint.values[3] = FORCE_UNIT(pcc->paint.values[3]);
    gx_restrict01_paint_3(pcc, pcs);
}

/* Null reference count adjustment procedure. */
void
gx_no_adjust_color_count(const gs_client_color * pcc,
			 const gs_color_space * pcs, int delta)
{
}

/* Forward declarations */
void load_transfer_map(gs_state *, gx_transfer_map *, floatp);

/* setgray */
int
gs_setgray(gs_state * pgs, floatp gray)
{
    gs_color_space      cs;
    int                 code;

    gs_cspace_init_DeviceGray(pgs->memory, &cs);
    if ((code = gs_setcolorspace(pgs, &cs)) >= 0) {
        gs_client_color *   pcc = pgs->ccolor;

        cs_adjust_color_count(pgs, -1); /* not strictly necessary */
        pcc->paint.values[0] = FORCE_UNIT(gray);
        pcc->pattern = 0;		/* for GC */
        gx_unset_dev_color(pgs);
    }
    return code;
}

/* setrgbcolor */
int
gs_setrgbcolor(gs_state * pgs, floatp r, floatp g, floatp b)
{
    gs_color_space      cs;
    int                 code;

    gs_cspace_init_DeviceRGB(pgs->memory, &cs);
    if ((code = gs_setcolorspace(pgs, &cs)) >= 0) {
       gs_client_color *    pcc = pgs->ccolor;

        cs_adjust_color_count(pgs, -1); /* not strictly necessary */
        pcc->paint.values[0] = FORCE_UNIT(r);
        pcc->paint.values[1] = FORCE_UNIT(g);
        pcc->paint.values[2] = FORCE_UNIT(b);
        pcc->pattern = 0;		/* for GC */
        gx_unset_dev_color(pgs);
    }
    return code;
}


/* setnullcolor */
int
gs_setnullcolor(gs_state * pgs)
{
    if (pgs->in_cachedevice)
	return_error(gs_error_undefined);
    gs_setgray(pgs, 0.0);	/* set color space to something harmless */
    color_set_null(pgs->dev_color);
    return 0;
}

/* settransfer */
/* Remap=0 is used by the interpreter. */
int
gs_settransfer(gs_state * pgs, gs_mapping_proc tproc)
{
    return gs_settransfer_remap(pgs, tproc, true);
}
int
gs_settransfer_remap(gs_state * pgs, gs_mapping_proc tproc, bool remap)
{
    gx_transfer *ptran = &pgs->set_transfer;

    /*
     * We can safely decrement the reference counts
     * of the non-default transfer maps, because
     * if any of them get freed, the rc_unshare can't fail.
     */
    rc_decrement(ptran->red, "gs_settransfer");
    rc_decrement(ptran->green, "gs_settransfer");
    rc_decrement(ptran->blue, "gs_settransfer");
    rc_unshare_struct(ptran->gray, gx_transfer_map, &st_transfer_map,
		      pgs->memory, goto fail, "gs_settransfer");
    ptran->gray->proc = tproc;
    ptran->gray->id = gs_next_ids(pgs->memory, 1);
    ptran->red = 0;
    ptran->green = 0;
    ptran->blue = 0;
    if (remap) {
	load_transfer_map(pgs, ptran->gray, 0.0);
	gx_set_effective_transfer(pgs);
	gx_unset_dev_color(pgs);
    } else
	gx_set_effective_transfer(pgs);
    return 0;
  fail:
    rc_increment(ptran->red);
    rc_increment(ptran->green);
    rc_increment(ptran->blue);
    rc_increment(ptran->gray);
    return_error(gs_error_VMerror);
}

/* currenttransfer */
gs_mapping_proc
gs_currenttransfer(const gs_state * pgs)
{
    return pgs->set_transfer.gray->proc;
}

/* ------ Non-operator routines ------ */

/* Set device color = 1 for writing into the character cache. */
void
gx_set_device_color_1(gs_state * pgs)
{
    gs_color_space  cs;

    gs_setoverprint(pgs, false);
    gs_setoverprintmode(pgs, 0);
    gs_cspace_init_DeviceGray(pgs->memory, &cs);
    gs_setcolorspace(pgs, &cs);
    set_nonclient_dev_color(pgs->dev_color, 1);
    pgs->log_op = lop_default;
    /*
     * In the unlikely event that  overprint mode is in effect,
     * update the overprint information.
     */
    if (pgs->effective_overprint_mode == 1)
	(void)gs_do_set_overprint(pgs);

}

/* ------ Internal routines ------ */

/*
 * Load one cached transfer map.  We export this for gscolor1.c.
 * Note that we must deal with both old (proc) and new (closure) maps.
 */
private float
transfer_use_proc(floatp value, const gx_transfer_map * pmap,
		  const void *ignore_proc_data)
{
    return (*pmap->proc) (value, pmap);
}
void
load_transfer_map(gs_state * pgs, gx_transfer_map * pmap, floatp min_value)
{
    gs_mapping_closure_proc_t proc;
    const void *proc_data;
    frac *values = pmap->values;
    frac fmin = float2frac(min_value);
    int i;

    if (pmap->proc == 0)	/* use closure */
	proc = pmap->closure.proc, proc_data = pmap->closure.data;
    else			/* use proc */
	proc = transfer_use_proc, proc_data = 0 /* not used */;
    for (i = 0; i < transfer_map_size; i++) {
	float fval =
	(*proc) ((float)i / (transfer_map_size - 1), pmap, proc_data);

	values[i] =
	    (fval < min_value ? fmin :
	     fval >= 1.0 ? frac_1 :
	     float2frac(fval));
    }
}