| /* |
| * Copyright (c) 1996, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * This file contains macro definitions for the Encoding category of |
| * the macros used by the generic scaleloop function. |
| * |
| * This implementation uses a Floyd-Steinberg error diffusion technique |
| * to produce a very high quality version of an image with only an 8-bit |
| * (or less) gray ramp. The error diffusion technique requires that the |
| * input color information be delivered in a special order from the top |
| * row to the bottom row and then left to right within each row, thus |
| * it is only valid in cases where the ImageProducer has specified the |
| * TopDownLeftRight delivery hint. If the data is not read in that order, |
| * no mathematical or memory access errors should occur, but the dithering |
| * error will be spread through the pixels of the output image in an |
| * unpleasant manner. |
| */ |
| |
| #include "img_fsutil.h" |
| |
| /* |
| * These definitions vector the standard macro names to the "Gray" |
| * versions of those macros only if the "DitherDeclared" keyword has |
| * not yet been defined elsewhere. The "DitherDeclared" keyword is |
| * also defined here to claim ownership of the primary implementation |
| * even though this file does not rely on the definitions in any other |
| * files. |
| */ |
| #ifndef DitherDeclared |
| #define DitherDeclared |
| #define DeclareDitherVars DeclareGrayDitherVars |
| #define InitDither InitGrayDither |
| #define StartDitherLine StartGrayDitherLine |
| #define DitherPixel GrayDitherPixel |
| #define DitherBufComplete GrayDitherBufComplete |
| #endif |
| |
| typedef struct { |
| int gray; |
| } GrayDitherError; |
| |
| #define DeclareGrayDitherVars \ |
| extern unsigned char img_grays[256]; \ |
| extern unsigned char img_bwgamma[256]; \ |
| int egray; \ |
| GrayDitherError *gep; |
| |
| #define InitGrayDither(cvdata, clrdata, dstTW) \ |
| do { \ |
| if (cvdata->fserrors == 0) { \ |
| int size = (dstTW + 2) * sizeof(GrayDitherError); \ |
| gep = (GrayDitherError *) sysMalloc(size); \ |
| if (gep == 0) { \ |
| SignalError(0, JAVAPKG "OutOfMemoryError", 0); \ |
| return SCALEFAILURE; \ |
| } \ |
| memset(gep, 0, size); \ |
| cvdata->fserrors = (void *) gep; \ |
| } \ |
| } while (0) |
| |
| |
| #define StartGrayDitherLine(cvdata, dstX1, dstY) \ |
| do { \ |
| gep = cvdata->fserrors; \ |
| if (dstX1) { \ |
| egray = gep[0].gray; \ |
| gep += dstX1; \ |
| } else { \ |
| egray = 0; \ |
| } \ |
| } while (0) |
| |
| #define GrayDitherPixel(dstX, dstY, pixel, red, green, blue) \ |
| do { \ |
| int e1, e2, e3; \ |
| \ |
| /* convert to gray value */ \ |
| e2 = RGBTOGRAY(red, green, blue); \ |
| \ |
| /* add previous errors */ \ |
| e2 += gep[1].gray; \ |
| \ |
| /* bounds checking */ \ |
| e2 = ComponentBound(e2); \ |
| \ |
| /* Store the closest color in the destination pixel */ \ |
| e2 = img_bwgamma[e2]; \ |
| pixel = img_grays[e2]; \ |
| GetPixelRGB(pixel, red, green, blue); \ |
| \ |
| /* Set the error from the previous lap */ \ |
| gep[1].gray = egray; \ |
| \ |
| /* compute the errors */ \ |
| egray = e2 - red; \ |
| \ |
| /* distribute the errors */ \ |
| DitherDist(gep, e1, e2, e3, egray, gray); \ |
| gep++; \ |
| } while (0) |
| |
| #define GrayDitherBufComplete(cvdata, dstX1) \ |
| do { \ |
| if (dstX1) { \ |
| gep = cvdata->fserrors; \ |
| gep[0].gray = egray; \ |
| } \ |
| } while (0) |
