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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/java/awt/color/GrayScaleConverter.java | |
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Diffstat (limited to 'libjava/classpath/gnu/java/awt/color/GrayScaleConverter.java')
-rw-r--r-- | libjava/classpath/gnu/java/awt/color/GrayScaleConverter.java | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/java/awt/color/GrayScaleConverter.java b/libjava/classpath/gnu/java/awt/color/GrayScaleConverter.java new file mode 100644 index 000000000..beea9d287 --- /dev/null +++ b/libjava/classpath/gnu/java/awt/color/GrayScaleConverter.java @@ -0,0 +1,110 @@ +/* GrayScaleConverter.java -- Linear grayscale conversion class + 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; + + +/** + * Linear Grayscale converter + * + * @author Sven de Marothy + */ +public class GrayScaleConverter implements ColorSpaceConverter +{ + // intensity factors (ITU Rec. BT.709) + double[] coeff = { 0.2125f, 0.7154f, 0.0721f }; + + /** + * CIE 1931 D50 white point (in Lab coordinates) + */ + private static float[] D50 = { 0.96422f, 1.00f, 0.82521f }; + + public float[] toCIEXYZ(float[] in) + { + float g = in[0]; + if (g < 0) + g = 1 + g; + float[] out = { g * D50[0], g * D50[1], g * D50[2] }; // White spot + return out; + } + + public float[] toRGB(float[] in) + { + float[] out = new float[3]; + if (in[0] <= 0.00304f) + out[0] = in[0] * 12.92f; + else + out[0] = 1.055f * ((float) Math.exp((1 / 2.4) * Math.log(in[0]))) + - 0.055f; + out[1] = out[2] = out[0]; + return out; + } + + public float[] fromCIEXYZ(float[] in) + { + float[] temp = new float[3]; + temp[0] = 3.1338f * in[0] - 1.6171f * in[1] - 0.4907f * in[2]; + temp[1] = -0.9785f * in[0] + 1.9160f * in[1] + 0.0334f * in[2]; + temp[2] = 0.0720f * in[0] - 0.2290f * in[1] + 1.4056f * in[2]; + float[] out = new float[1]; + for (int i = 0; i < 3; i++) + out[0] = (float) (temp[i] * coeff[i]); + return out; + } + + public float[] fromRGB(float[] in) + { + float[] out = new float[1]; + + // Convert non-linear RGB coordinates to linear ones, + // numbers from the w3 spec. + out[0] = 0; + 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[0] += (float) (coeff[i] * n / 12.92); + else + out[0] += (float) (coeff[i] * Math.exp(2.4 * Math.log((n + 0.055) / 1.055))); + } + return out; + } +} |