svn commit: r1420517 - /commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java

[da...@apache.org]

Author: damjan
Date: Wed Dec 12 04:26:16 2012
New Revision: 1420517

URL: http://svn.apache.org/viewvc?rev=1420517&view=rev
Log:
Add a Floyd-Steinberg dithering implementation.


Added:
    commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java   (with props)

Added: commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java
URL: http://svn.apache.org/viewvc/commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java?rev=1420517&view=auto
==============================================================================
--- commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java (added)
+++ commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java Wed Dec 12 04:26:16 2012
@@ -0,0 +1,102 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.imaging.palette;
+
+import java.awt.image.BufferedImage;
+
+import org.apache.commons.imaging.ImageWriteException;
+
+public class Dithering {
+    public static void applyFloydSteinbergDithering(BufferedImage image, Palette palette) throws ImageWriteException {
+        for (int y = 0; y < image.getHeight(); y++) {
+            for (int x = 0; x < image.getWidth(); x++) {
+                int argb = image.getRGB(x, y);
+                int index = palette.getPaletteIndex(argb);
+                int nextArgb = palette.getEntry(index);
+                image.setRGB(x, y, nextArgb);
+                
+                int a = (argb >> 24) & 0xff;
+                int r = (argb >> 16) & 0xff;
+                int g = (argb >> 8) & 0xff;
+                int b = argb & 0xff;
+                
+                int na = (nextArgb >> 24) & 0xff;
+                int nr = (nextArgb >> 16) & 0xff;
+                int ng = (nextArgb >> 8) & 0xff;
+                int nb = nextArgb & 0xff;
+
+                int errA = a - na;
+                int errR = r - nr;
+                int errG = g - ng;
+                int errB = b - nb;
+                
+                if (x + 1 < image.getWidth()) {
+                    int update = adjustPixel(image.getRGB(x + 1, y), errA, errR, errG, errB, 7);
+                    image.setRGB(x + 1, y, update);
+                    if (y + 1 < image.getHeight()) {
+                        update = adjustPixel(image.getRGB(x + 1, y + 1), errA, errR, errG, errB, 1);
+                        image.setRGB(x + 1, y + 1, update);
+                    }
+                }
+                if (y + 1 < image.getHeight()) {
+                    int update = adjustPixel(image.getRGB(x, y + 1), errA, errR, errG, errB, 5);
+                    image.setRGB(x, y + 1, update);
+                    if (x - 1 >= 0) {
+                        update = adjustPixel(image.getRGB(x - 1, y + 1), errA, errR, errG, errB, 3);
+                        image.setRGB(x - 1, y + 1, update);
+                    }
+
+                }
+            }
+        }
+    }
+    
+    private static int adjustPixel(int argb, int errA, int errR, int errG, int errB, int mul) {
+        int a = (argb >> 24) & 0xff;
+        int r = (argb >> 16) & 0xff;
+        int g = (argb >> 8) & 0xff;
+        int b = argb & 0xff;
+        
+        a += errA*mul/16;
+        r += errR*mul/16;
+        g += errG*mul/16;
+        b += errB*mul/16;
+        
+        if (a < 0) {
+            a = 0;
+        } else if (a > 0xff) {
+            a = 0xff;
+        }
+        if (r < 0) {
+            r = 0;
+        } else if (r > 0xff) {
+            r = 0xff;
+        }
+        if (g < 0) {
+            g = 0;
+        } else if (g > 0xff) {
+            g = 0xff;
+        }
+        if (b < 0) {
+            b = 0;
+        } else if (b > 0xff) {
+            b = 0xff;
+        }
+
+        return (a << 24) | (r << 16) | (g << 8) | b;
+    }
+}

Propchange: commons/proper/imaging/trunk/src/main/java/org/apache/commons/imaging/palette/Dithering.java
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