1/*
2 * Copyright (c) 1996, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26/*
27 * This file contains macro definitions for the Encoding category of
28 * the macros used by the generic scaleloop function.
29 *
30 * This implementation uses an ordered dithering error matrix with
31 * signed error adjustments to produce a moderately high quality
32 * version of an image with only an 8-bit (or less) RGB colormap and
33 * a "closest color" lookup table.  The ordered dithering technique
34 * does not rely on the order in which the pixels are processed so
35 * this file can be used in cases where the ImageProducer has not
36 * specified the TopDownLeftRight delivery hint.  The ordered dither
37 * technique is also much faster than the Floyd-Steinberg error diffusion
38 * algorithm so this implementation would also be appropriate for
39 * cases where performance is critical such as the processing of a
40 * video stream.
41 *
42 * This file can be used to provide the default implementation of the
43 * Encoding macros for RGB colormapped displays.
44 */
45
46/*
47 * These definitions vector the standard macro names to the "Color"
48 * versions of those macros only if the "DitherDeclared" keyword has
49 * not yet been defined elsewhere.  The "DitherDeclared" keyword is
50 * also defined here to claim ownership of the primary implementation
51 * even though this file does not rely on the definitions in any other
52 * files.
53 */
54#ifndef DitherDeclared
55#define DitherDeclared
56#define DeclareDitherVars       DeclareAllColorDitherVars
57#define InitDither              InitColorDither
58#define StartDitherLine         StartColorDitherLine
59#define DitherPixel             ColorDitherPixel
60#define DitherBufComplete       ColorDitherBufComplete
61#endif
62
63#define DeclareAllColorDitherVars                       \
64    DeclareColorDitherVars                              \
65    int relx, rely;
66
67#define DeclareColorDitherVars                          \
68    extern sgn_ordered_dither_array img_oda_red;        \
69    extern sgn_ordered_dither_array img_oda_green;      \
70    extern sgn_ordered_dither_array img_oda_blue;
71
72#define InitColorDither(cvdata, clrdata, dstTW)                 \
73    do {} while (0)
74
75#define StartColorDitherLine(cvdata, dstX1, dstY)               \
76    do {                                                        \
77        relx = dstX1 & 7;                                       \
78        rely = dstY & 7;                                        \
79    } while (0)
80
81#define ColorDitherPixel(dstX, dstY, pixel, red, green, blue)   \
82    do {                                                        \
83        red += img_oda_red[relx][rely];                         \
84        red = ComponentBound(red);                              \
85        green += img_oda_green[relx][rely];                     \
86        green = ComponentBound(green);                          \
87        blue += img_oda_blue[relx][rely];                       \
88        blue = ComponentBound(blue);                            \
89        pixel = ColorCubeOrdMapSgn(red, green, blue);           \
90        relx = (relx + 1) & 7;                                  \
91    } while (0)
92
93#define ColorDitherBufComplete(cvdata, dstX1)                   \
94    do {} while (0)
95