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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.h,v 1.5 2002/06/16 07:25:26 lpd Exp $ */
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/* 8-bit color map support */
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/* Requires gxdevice.h (for gx_color_value) */
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#ifndef gdev8bcm_INCLUDED
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# define gdev8bcm_INCLUDED
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/*
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* The MS-DOS, MS Windows, and X Windows drivers all use (at least on
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* some platforms) an 8-bit color map in which some fraction is reserved
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* for a pre-allocated cube and some or all of the remainder is
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* allocated dynamically. Since looking up colors in this map can be
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* a major performance bottleneck, we provide an efficient implementation
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* that can be shared among drivers.
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*
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* As a performance compromise, we only look up the top 5 bits of the
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* RGB value in the color map. This compromises color quality very little,
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* and allows substantial optimizations.
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*/
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#define gx_8bit_map_size 323
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#define gx_8bit_map_spreader 123 /* approx. 323 - (1.618 * 323) */
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typedef struct gx_8bit_map_entry_s {
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ushort rgb; /* key = 0rrrrrgggggbbbbb */
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#define gx_8bit_no_rgb ((ushort)0xffff)
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#define gx_8bit_rgb_key(r, g, b)\
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(((r >> (gx_color_value_bits - 5)) << 10) +\
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((g >> (gx_color_value_bits - 5)) << 5) +\
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(b >> (gx_color_value_bits - 5)))
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short index; /* value */
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} gx_8bit_map_entry;
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typedef struct gx_8bit_color_map_s {
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int count; /* # of occupied entries */
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int max_count; /* max # of occupied entries */
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gx_8bit_map_entry map[gx_8bit_map_size + 1];
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} gx_8bit_color_map;
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/* Initialize an 8-bit color map. */
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void gx_8bit_map_init(gx_8bit_color_map *, int);
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/* Look up a color in an 8-bit color map. */
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/* Return -1 if not found. */
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int gx_8bit_map_rgb_color(const gx_8bit_color_map *, gx_color_value,
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gx_color_value, gx_color_value);
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/* Test whether an 8-bit color map has room for more entries. */
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#define gx_8bit_map_is_full(pcm)\
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((pcm)->count == (pcm)->max_count)
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/* Add a color to an 8-bit color map. */
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/* Return -1 if the map is full. */
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int gx_8bit_add_rgb_color(gx_8bit_color_map *, gx_color_value,
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gx_color_value, gx_color_value);
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#endif /* gdev8bcm_INCLUDED */
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