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Diffstat (limited to 'libjava/classpath/gnu/javax/imageio/jpeg/DCT.java')
| -rw-r--r-- | libjava/classpath/gnu/javax/imageio/jpeg/DCT.java | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/imageio/jpeg/DCT.java b/libjava/classpath/gnu/javax/imageio/jpeg/DCT.java new file mode 100644 index 000000000..fda52e5f5 --- /dev/null +++ b/libjava/classpath/gnu/javax/imageio/jpeg/DCT.java @@ -0,0 +1,347 @@ +/* DCT.java -- + Copyright (C) 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.javax.imageio.jpeg; + +/** + * Discrete Cosine Transformations. + */ +public class DCT +{ + + /** + * Cosine matrix + */ + public double c[][] = new double[8][8]; + + /** + * Transformed cosine matrix + */ + public double cT[][] = new double[8][8]; + + public DCT() + { + initMatrix(); + } + + /** + * Figure A.3.3 IDCT, Cu Cv on A-5 of the ISO DIS 10918-1. Requirements and + * Guidelines. + * + * @param u + * @return + */ + public static double C(int u) + { + return ((u == 0) ? (double) 1 / (double) Math.sqrt((double) 2) + : (double) 1); + } + + /** + * Initialize matrix values for the fast_idct function + */ + private void initMatrix() + { + for (int j = 0; j < 8; j++) + { + double nn = (double) (8); + c[0][j] = 1.0 / Math.sqrt(nn); + cT[j][0] = c[0][j]; + } + for (int i = 1; i < 8; i++) + { + for (int j = 0; j < 8; j++) + { + double jj = (double) j; + double ii = (double) i; + c[i][j] = + Math.sqrt(2.0 / 8.0) + * Math.cos(((2.0 * jj + 1.0) * ii * Math.PI) / (2.0 * 8.0)); + cT[j][i] = c[i][j]; + } + } + } + + /** + * slow_idct - Figure A.3.3 IDCT (informative) on A-5 of the ISO DIS + * 10918-1. Requirements and Guidelines. This is a slow IDCT, there are + * better algorithms to use, it's fairly expensive with processor speed. + * + * @param matrix + * @return + */ + public static double[][] slow_idct(double[][] matrix) + { + double[][] output = new double[matrix.length][matrix.length]; + for (int y = 0; y < 8; y++) + { + for (int x = 0; x < 8; x++) + { + double val = 0; + for (double v = 0; v < 8; v++) + { + double innerloop = 0; + for (double u = 0; u < 8; u++) + innerloop += (DCT.C((int) u) / (double) 2) + * matrix[(int) v][(int) u] + * Math.cos((2 * x + 1) * u * Math.PI / (double) 16) + * Math.cos((2 * y + 1) * v * Math.PI / (double) 16); + val += (DCT.C((int) v) / (double) 2) * innerloop; + } + output[y][x] = (val + 128); + } + } + return (output); + } + + public static float[][] slow_fdct(float[][] value) + { + float[][] buffer = new float[8][8]; + + for (int u = 0; u < 8; u++) + { + for (int v = 0; v < 8; v++) + { + buffer[u][v] = + (float) (1 / 4) * (float) C((int) u) * (float) C((int) v); + float innerval = 0; + for (int x = 0; x < 8; x++) + { + for (int y = 0; y < 8; y++) + { + innerval += value[y][x] + * Math.cos(((2 * x + 1) * u * Math.PI) / 16) + * Math.cos(((2 * y + 1) * v * Math.PI) / 16); + } + } + buffer[u][v] *= innerval; + } + } + return (buffer); + } + + public float[][] fast_fdct(float[][] input) + { + float output[][] = new float[8][8]; + double temp[][] = new double[8][8]; + double temp1; + int i; + int j; + int k; + + for (i = 0; i < 8; i++) + { + for (j = 0; j < 8; j++) + { + temp[i][j] = 0.0; + for (k = 0; k < 8; k++) + { + temp[i][j] += (((int) (input[i][k]) - 128) * cT[k][j]); + } + } + } + + for (i = 0; i < 8; i++) + { + for (j = 0; j < 8; j++) + { + temp1 = 0.0; + + for (k = 0; k < 8; k++) + { + temp1 += (c[i][k] * temp[k][j]); + } + + output[i][j] = (int) Math.round(temp1) * 8; + } + } + + return output; + } + + /** + * fast_idct - Figure A.3.3 IDCT (informative) on A-5 of the ISO DIS + * 10918-1. Requires and Guidelines. This is a fast IDCT, it much more + * effecient and only inaccurate at about 1/1000th of a percent of values + * analyzed. Cannot be static because initMatrix must run before any + * fast_idct values can be computed. + * + * @param input + * @return + */ + public double[][] fast_idct(double[][] input) + { + double output[][] = new double[8][8]; + double temp[][] = new double[8][8]; + double temp1; + int i, j, k; + for (i = 0; i < 8; i++) + { + for (j = 0; j < 8; j++) + { + temp[i][j] = 0.0; + for (k = 0; k < 8; k++) + { + temp[i][j] += input[i][k] * c[k][j]; + } + } + } + for (i = 0; i < 8; i++) + { + for (j = 0; j < 8; j++) + { + temp1 = 0.0; + for (k = 0; k < 8; k++) + temp1 += cT[i][k] * temp[k][j]; + temp1 += 128.0; + if (temp1 < 0) + output[i][j] = 0; + else if (temp1 > 255) + output[i][j] = 255; + else + output[i][j] = (int) Math.round(temp1); + } + } + return output; + } + + public double[][] idj_fast_fdct(float input[][]) + { + double output[][] = new double[8][8]; + double tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; + double tmp10, tmp11, tmp12, tmp13; + double z1, z2, z3, z4, z5, z11, z13; + int i; + int j; + + // Subtracts 128 from the input values + for (i = 0; i < 8; i++) + { + for (j = 0; j < 8; j++) + { + output[i][j] = ((double) input[i][j] - (double) 128.0); + // input[i][j] -= 128; + + } + } + + for (i = 0; i < 8; i++) + { + tmp0 = output[i][0] + output[i][7]; + tmp7 = output[i][0] - output[i][7]; + tmp1 = output[i][1] + output[i][6]; + tmp6 = output[i][1] - output[i][6]; + tmp2 = output[i][2] + output[i][5]; + tmp5 = output[i][2] - output[i][5]; + tmp3 = output[i][3] + output[i][4]; + tmp4 = output[i][3] - output[i][4]; + + tmp10 = tmp0 + tmp3; + tmp13 = tmp0 - tmp3; + tmp11 = tmp1 + tmp2; + tmp12 = tmp1 - tmp2; + + output[i][0] = tmp10 + tmp11; + output[i][4] = tmp10 - tmp11; + + z1 = (tmp12 + tmp13) * (double) 0.707106781; + output[i][2] = tmp13 + z1; + output[i][6] = tmp13 - z1; + + tmp10 = tmp4 + tmp5; + tmp11 = tmp5 + tmp6; + tmp12 = tmp6 + tmp7; + + z5 = (tmp10 - tmp12) * (double) 0.382683433; + z2 = ((double) 0.541196100) * tmp10 + z5; + z4 = ((double) 1.306562965) * tmp12 + z5; + z3 = tmp11 * ((double) 0.707106781); + + z11 = tmp7 + z3; + z13 = tmp7 - z3; + + output[i][5] = z13 + z2; + output[i][3] = z13 - z2; + output[i][1] = z11 + z4; + output[i][7] = z11 - z4; + } + + for (i = 0; i < 8; i++) + { + tmp0 = output[0][i] + output[7][i]; + tmp7 = output[0][i] - output[7][i]; + tmp1 = output[1][i] + output[6][i]; + tmp6 = output[1][i] - output[6][i]; + tmp2 = output[2][i] + output[5][i]; + tmp5 = output[2][i] - output[5][i]; + tmp3 = output[3][i] + output[4][i]; + tmp4 = output[3][i] - output[4][i]; + + tmp10 = tmp0 + tmp3; + tmp13 = tmp0 - tmp3; + tmp11 = tmp1 + tmp2; + tmp12 = tmp1 - tmp2; + + output[0][i] = tmp10 + tmp11; + output[4][i] = tmp10 - tmp11; + + z1 = (tmp12 + tmp13) * (double) 0.707106781; + output[2][i] = tmp13 + z1; + output[6][i] = tmp13 - z1; + + tmp10 = tmp4 + tmp5; + tmp11 = tmp5 + tmp6; + tmp12 = tmp6 + tmp7; + + z5 = (tmp10 - tmp12) * (double) 0.382683433; + z2 = ((double) 0.541196100) * tmp10 + z5; + z4 = ((double) 1.306562965) * tmp12 + z5; + z3 = tmp11 * ((double) 0.707106781); + + z11 = tmp7 + z3; + z13 = tmp7 - z3; + + output[5][i] = z13 + z2; + output[3][i] = z13 - z2; + output[1][i] = z11 + z4; + output[7][i] = z11 - z4; + } + + return output; + } + +} |