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Diffstat (limited to 'gcc-4.4.3/libjava/classpath/gnu/java/awt/color/LinearRGBConverter.java')
| -rw-r--r-- | gcc-4.4.3/libjava/classpath/gnu/java/awt/color/LinearRGBConverter.java | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/gcc-4.4.3/libjava/classpath/gnu/java/awt/color/LinearRGBConverter.java b/gcc-4.4.3/libjava/classpath/gnu/java/awt/color/LinearRGBConverter.java new file mode 100644 index 000000000..13a4e2c04 --- /dev/null +++ b/gcc-4.4.3/libjava/classpath/gnu/java/awt/color/LinearRGBConverter.java @@ -0,0 +1,152 @@ +/* LinearRGBConverter.java -- conversion to a linear RGB color space + Copyright (C) 2004 Free Software Foundation + +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.java.awt.color; + + +/** + * LinearRGBConverter - conversion routines for a linear sRGB colorspace + * sRGB is a standard for RGB colorspaces, adopted by the w3c. + * + * The specification is available at: + * http://www.w3.org/Graphics/Color/sRGB.html + * + * @author Sven de Marothy + */ +public class LinearRGBConverter implements ColorSpaceConverter +{ + /** + * linear RGB --> sRGB + * Use the inverse gamma curve + */ + public float[] toRGB(float[] in) + { + float[] out = new float[3]; + for (int i = 0; i < 3; i++) + { + float n = in[i]; + if (n < 0) + n = 0f; + if (n > 1) + n = 1f; + if (n <= 0.00304f) + out[i] = in[0] * 12.92f; + else + out[i] = 1.055f * ((float) Math.exp((1 / 2.4) * Math.log(n))) + - 0.055f; + } + return out; + } + + /** + * sRGB --> linear RGB + * Use the gamma curve (gamma=2.4 in sRGB) + */ + public float[] fromRGB(float[] in) + { + float[] out = new float[3]; + + // Convert non-linear RGB coordinates to linear ones, + // numbers from the w3 spec. + for (int i = 0; i < 3; i++) + { + float n = in[i]; + if (n < 0) + n = 0f; + if (n > 1) + n = 1f; + if (n <= 0.03928f) + out[i] = (float) (n / 12.92); + else + out[i] = (float) (Math.exp(2.4 * Math.log((n + 0.055) / 1.055))); + } + return out; + } + + /** + * Linear RGB --> CIE XYZ (D50 relative) + * This is a simple matrix transform, the matrix (relative D65) + * is given in the sRGB spec. This has been combined with a + * linear Bradford transform for the D65-->D50 mapping, resulting + * in a single matrix which does the whole thing. + * + */ + public float[] fromCIEXYZ(float[] in) + { + /* + * Note: The numbers which were used to calculate this only had four + * digits of accuracy. So don't be fooled by the number of digits here. + * If someone has more accurate source, feel free to update this. + */ + float[] out = new float[3]; + out[0] = (float) (3.13383065124221 * in[0] - 1.61711949411313 * in[1] + - 0.49071914111101 * in[2]); + out[1] = (float) (-0.97847026691142 * in[0] + 1.91597856031996 * in[1] + + 0.03340430640699 * in[2]); + out[2] = (float) (0.07203679486279 * in[0] - 0.22903073553113 * in[1] + + 1.40557835776234 * in[2]); + if (out[0] < 0) + out[0] = 0f; + if (out[1] < 0) + out[1] = 0f; + if (out[2] < 0) + out[2] = 0f; + if (out[0] > 1.0f) + out[0] = 1.0f; + if (out[1] > 1.0f) + out[1] = 1.0f; + if (out[2] > 1.0f) + out[2] = 1.0f; + return out; + } + + /** + * Linear RGB --> CIE XYZ (D50 relative) + * Uses the inverse of the above matrix. + */ + public float[] toCIEXYZ(float[] in) + { + float[] out = new float[3]; + out[0] = (float) (0.43606375022190 * in[0] + 0.38514960146481 * in[1] + + 0.14308641888799 * in[2]); + out[1] = (float) (0.22245089403542 * in[0] + 0.71692584775182 * in[1] + + 0.06062451125578 * in[2]); + out[2] = (float) (0.01389851860679 * in[0] + 0.09707969011198 * in[1] + + 0.71399604572506 * in[2]); + return out; + } +} |