| /* |
| * Copyright (c) 1996, 2018, 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 implements some of the standard utility procedures used |
| * by the image conversion package. |
| */ |
| |
| #include "jni.h" |
| #include "img_globals.h" |
| |
| #include "java_awt_image_IndexColorModel.h" |
| #include "java_awt_Transparency.h" |
| |
| /* |
| * This function constructs an 8x8 ordered dither array which can be |
| * used to dither data into an output range with discreet values that |
| * differ by the value specified as quantum. A monochrome screen would |
| * use a dither array constructed with the quantum 256. |
| * The array values produced are unsigned and intended to be used with |
| * a lookup table which returns the next color darker than the error |
| * adjusted color used as the index. |
| */ |
| JNIEXPORT void JNICALL |
| make_uns_ordered_dither_array(uns_ordered_dither_array oda, |
| int quantum) |
| { |
| int i, j, k; |
| |
| oda[0][0] = 0; |
| for (k = 1; k < 8; k *= 2) { |
| for (i = 0; i < k; i++) { |
| for (j = 0; j < k; j++) { |
| oda[ i ][ j ] = oda[i][j] * 4; |
| oda[i+k][j+k] = oda[i][j] + 1; |
| oda[ i ][j+k] = oda[i][j] + 2; |
| oda[i+k][ j ] = oda[i][j] + 3; |
| } |
| } |
| } |
| for (i = 0; i < 8; i++) { |
| for (j = 0; j < 8; j++) { |
| oda[i][j] = oda[i][j] * quantum / 64; |
| } |
| } |
| } |
| |
| /* |
| * This function constructs an 8x8 ordered dither array which can be |
| * used to dither data into an output range with discreet values that |
| * are distributed over the range from minerr to maxerr around a given |
| * target color value. |
| * The array values produced are signed and intended to be used with |
| * a lookup table which returns the closest color to the error adjusted |
| * color used as an index. |
| */ |
| void |
| make_sgn_ordered_dither_array(char* oda, int minerr, int maxerr) |
| { |
| int i, j, k; |
| |
| oda[0] = 0; |
| for (k = 1; k < 8; k *= 2) { |
| for (i = 0; i < k; i++) { |
| for (j = 0; j < k; j++) { |
| oda[(i<<3) + j] = oda[(i<<3)+j] * 4; |
| oda[((i+k)<<3) + j+k] = oda[(i<<3)+j] + 1; |
| oda[(i<<3) + j+k] = oda[(i<<3)+j] + 2; |
| oda[((i+k)<<3) + j] = oda[(i<<3)+j] + 3; |
| } |
| } |
| } |
| k = 0; |
| for (i = 0; i < 8; i++) { |
| for (j = 0; j < 8; j++) { |
| oda[k] = oda[k] * (maxerr - minerr) / 64 + minerr; |
| k++; |
| } |
| } |
| } |
| |
| #ifdef TESTING |
| #include <stdio.h> |
| |
| /* Function to test the ordered dither error matrix initialization function. */ |
| main(int argc, char **argv) |
| { |
| int i, j; |
| int quantum; |
| int max, val; |
| uns_ordered_dither_array oda; |
| |
| if (argc > 1) { |
| quantum = atoi(argv[1]); |
| } else { |
| quantum = 64; |
| } |
| make_uns_ordered_dither_array(oda, quantum); |
| for (i = 0; i < 8; i++) { |
| for (j = 0; j < 8; j++) { |
| val = oda[i][j]; |
| printf("%4d", val); |
| if (max < val) { |
| max = val; |
| } |
| } |
| printf("\n"); |
| } |
| printf("\nmax = %d\n", max); |
| } |
| #endif /* TESTING */ |
