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/* Copyright (C) 1994 Aladdin Enterprises. All rights reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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For more information about licensing, please refer to
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http://www.ghostscript.com/licensing/. For information on
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commercial licensing, go to http://www.artifex.com/licensing/ or
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contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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/* $Id: gdev8bcm.c,v 1.4 2002/02/21 22:24:51 giles Exp $ */
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/* Dynamic color mapping for 8-bit displays */
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#include "gx.h"
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#include "gxdevice.h"
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#include "gdev8bcm.h"
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/* Initialize an 8-bit color map. */
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void
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gx_8bit_map_init(gx_8bit_color_map * pcm, int max_count)
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{
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int i;
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pcm->count = 0;
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pcm->max_count = max_count;
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for (i = 0; i < gx_8bit_map_size; i++)
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pcm->map[i].rgb = gx_8bit_no_rgb;
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}
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/* Look up a color in an 8-bit color map. */
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/* Return <0 if not found. */
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int
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gx_8bit_map_rgb_color(const gx_8bit_color_map * pcm, gx_color_value r,
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gx_color_value g, gx_color_value b)
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{
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ushort rgb = gx_8bit_rgb_key(r, g, b);
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const gx_8bit_map_entry *pme =
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&pcm->map[(rgb * gx_8bit_map_spreader) % gx_8bit_map_size];
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for (;; pme++) {
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if (pme->rgb == rgb)
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return pme->index;
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else if (pme->rgb == gx_8bit_no_rgb)
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break;
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}
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if (pme != &pcm->map[gx_8bit_map_size])
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return pme - &pcm->map[gx_8bit_map_size];
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/* We ran off the end; wrap around and continue. */
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pme = &pcm->map[0];
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for (;; pme++) {
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if (pme->rgb == rgb)
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return pme->index;
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else if (pme->rgb == gx_8bit_no_rgb)
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return pme - &pcm->map[gx_8bit_map_size];
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}
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}
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/* Add a color to an 8-bit color map after an unsuccessful lookup, */
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/* and return its index. Return <0 if the map is full. */
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int
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gx_8bit_add_rgb_color(gx_8bit_color_map * pcm, gx_color_value r,
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gx_color_value g, gx_color_value b)
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{
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int index;
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gx_8bit_map_entry *pme;
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if (gx_8bit_map_is_full(pcm))
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return -1;
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index = gx_8bit_map_rgb_color(pcm, r, g, b);
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if (index >= 0) /* shouldn't happen */
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return index;
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pme = &pcm->map[-index];
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pme->rgb = gx_8bit_rgb_key(r, g, b);
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return (pme->index = pcm->count++);
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}
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