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