ojluni/src/main/java/javax/swing/plaf/nimbus/EffectUtils.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2005, 2006, 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.
  */
 package javax.swing.plaf.nimbus;

 import java.awt.AlphaComposite;
 import java.awt.Graphics2D;
 import java.awt.Transparency;
 import java.awt.GraphicsConfiguration;
 import java.awt.GraphicsEnvironment;
 import java.awt.image.BufferedImage;
 import java.awt.image.Raster;
 import java.awt.image.WritableRaster;
 import java.awt.image.ColorModel;

 /**
  * EffectUtils
  *
  * @author Created by Jasper Potts (Jun 18, 2007)
  */
 class EffectUtils {

     /**
      * Clear a transparent image to 100% transparent
      *
      * @param img The image to clear
      */
     static void clearImage(BufferedImage img) {
         Graphics2D g2 = img.createGraphics();
         g2.setComposite(AlphaComposite.Clear);
         g2.fillRect(0, 0, img.getWidth(), img.getHeight());
         g2.dispose();
     }

     // =================================================================================================================
     // Blur

     /**
      * Apply Gaussian Blur to Image
      *
      * @param src    The image tp
      * @param dst    The destination image to draw blured src image into, null if you want a new one created
      * @param radius The blur kernel radius
      * @return The blured image
      */
     static BufferedImage gaussianBlur(BufferedImage src, BufferedImage dst, int radius) {
         int width = src.getWidth();
         int height = src.getHeight();
         if (dst == null || dst.getWidth() != width || dst.getHeight() != height || src.getType() != dst.getType()) {
             dst = createColorModelCompatibleImage(src);
         }
         float[] kernel = createGaussianKernel(radius);
         if (src.getType() == BufferedImage.TYPE_INT_ARGB) {
             int[] srcPixels = new int[width * height];
             int[] dstPixels = new int[width * height];
             getPixels(src, 0, 0, width, height, srcPixels);
             // horizontal pass
             blur(srcPixels, dstPixels, width, height, kernel, radius);
             // vertical pass
             //noinspection SuspiciousNameCombination
             blur(dstPixels, srcPixels, height, width, kernel, radius);
             // the result is now stored in srcPixels due to the 2nd pass
             setPixels(dst, 0, 0, width, height, srcPixels);
         } else if (src.getType() == BufferedImage.TYPE_BYTE_GRAY) {
             byte[] srcPixels = new byte[width * height];
             byte[] dstPixels = new byte[width * height];
             getPixels(src, 0, 0, width, height, srcPixels);
             // horizontal pass
             blur(srcPixels, dstPixels, width, height, kernel, radius);
             // vertical pass
             //noinspection SuspiciousNameCombination
             blur(dstPixels, srcPixels, height, width, kernel, radius);
             // the result is now stored in srcPixels due to the 2nd pass
             setPixels(dst, 0, 0, width, height, srcPixels);
         } else {
             throw new IllegalArgumentException("EffectUtils.gaussianBlur() src image is not a supported type, type=[" +
                     src.getType() + "]");
         }
         return dst;
     }

     /**
      * <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by the radius which
      * must be greater than 0.</p> <p>The source and destination pixels arrays are expected to be in the INT_ARGB
      * format.</p> <p>After this method is executed, dstPixels contains a transposed and filtered copy of
      * srcPixels.</p>
      *
      * @param srcPixels the source pixels
      * @param dstPixels the destination pixels
      * @param width     the width of the source picture
      * @param height    the height of the source picture
      * @param kernel    the kernel of the blur effect
      * @param radius    the radius of the blur effect
      */
     private static void blur(int[] srcPixels, int[] dstPixels,
                              int width, int height,
                              float[] kernel, int radius) {
         float a;
         float r;
         float g;
         float b;

         int ca;
         int cr;
         int cg;
         int cb;

         for (int y = 0; y < height; y++) {
             int index = y;
             int offset = y * width;

             for (int x = 0; x < width; x++) {
                 a = r = g = b = 0.0f;

                 for (int i = -radius; i <= radius; i++) {
                     int subOffset = x + i;
                     if (subOffset < 0 || subOffset >= width) {
                         subOffset = (x + width) % width;
                     }

                     int pixel = srcPixels[offset + subOffset];
                     float blurFactor = kernel[radius + i];

                     a += blurFactor * ((pixel >> 24) & 0xFF);
                     r += blurFactor * ((pixel >> 16) & 0xFF);
                     g += blurFactor * ((pixel >> 8) & 0xFF);
                     b += blurFactor * ((pixel) & 0xFF);
                 }

                 ca = (int) (a + 0.5f);
                 cr = (int) (r + 0.5f);
                 cg = (int) (g + 0.5f);
                 cb = (int) (b + 0.5f);

                 dstPixels[index] = ((ca > 255 ? 255 : ca) << 24) |
                         ((cr > 255 ? 255 : cr) << 16) |
                         ((cg > 255 ? 255 : cg) << 8) |
                         (cb > 255 ? 255 : cb);
                 index += height;
             }
         }
     }

     /**
      * <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by the radius which
      * must be greater than 0.</p> <p>The source and destination pixels arrays are expected to be in the BYTE_GREY
      * format.</p> <p>After this method is executed, dstPixels contains a transposed and filtered copy of
      * srcPixels.</p>
      *
      * @param srcPixels the source pixels
      * @param dstPixels the destination pixels
      * @param width     the width of the source picture
      * @param height    the height of the source picture
      * @param kernel    the kernel of the blur effect
      * @param radius    the radius of the blur effect
      */
     static void blur(byte[] srcPixels, byte[] dstPixels,
                             int width, int height,
                             float[] kernel, int radius) {
         float p;
         int cp;
         for (int y = 0; y < height; y++) {
             int index = y;
             int offset = y * width;
             for (int x = 0; x < width; x++) {
                 p = 0.0f;
                 for (int i = -radius; i <= radius; i++) {
                     int subOffset = x + i;
 //                    if (subOffset < 0) subOffset = 0;
 //                    if (subOffset >= width) subOffset = width-1;
                     if (subOffset < 0 || subOffset >= width) {
                         subOffset = (x + width) % width;
                     }
                     int pixel = srcPixels[offset + subOffset] & 0xFF;
                     float blurFactor = kernel[radius + i];
                     p += blurFactor * pixel;
                 }
                 cp = (int) (p + 0.5f);
                 dstPixels[index] = (byte) (cp > 255 ? 255 : cp);
                 index += height;
             }
         }
     }

     static float[] createGaussianKernel(int radius) {
         if (radius < 1) {
             throw new IllegalArgumentException("Radius must be >= 1");
         }

         float[] data = new float[radius * 2 + 1];

         float sigma = radius / 3.0f;
         float twoSigmaSquare = 2.0f * sigma * sigma;
         float sigmaRoot = (float) Math.sqrt(twoSigmaSquare * Math.PI);
         float total = 0.0f;

         for (int i = -radius; i <= radius; i++) {
             float distance = i * i;
             int index = i + radius;
             data[index] = (float) Math.exp(-distance / twoSigmaSquare) / sigmaRoot;
             total += data[index];
         }

         for (int i = 0; i < data.length; i++) {
             data[i] /= total;
         }

         return data;
     }

     // =================================================================================================================
     // Get/Set Pixels helper methods

     /**
      * <p>Returns an array of pixels, stored as integers, from a <code>BufferedImage</code>. The pixels are grabbed from
      * a rectangular area defined by a location and two dimensions. Calling this method on an image of type different
      * from <code>BufferedImage.TYPE_INT_ARGB</code> and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the
      * image.</p>
      *
      * @param img    the source image
      * @param x      the x location at which to start grabbing pixels
      * @param y      the y location at which to start grabbing pixels
      * @param w      the width of the rectangle of pixels to grab
      * @param h      the height of the rectangle of pixels to grab
      * @param pixels a pre-allocated array of pixels of size w*h; can be null
      * @return <code>pixels</code> if non-null, a new array of integers otherwise
      * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h
      */
     static byte[] getPixels(BufferedImage img,
                                    int x, int y, int w, int h, byte[] pixels) {
         if (w == 0 || h == 0) {
             return new byte[0];
         }

         if (pixels == null) {
             pixels = new byte[w * h];
         } else if (pixels.length < w * h) {
             throw new IllegalArgumentException("pixels array must have a length >= w*h");
         }

         int imageType = img.getType();
         if (imageType == BufferedImage.TYPE_BYTE_GRAY) {
             Raster raster = img.getRaster();
             return (byte[]) raster.getDataElements(x, y, w, h, pixels);
         } else {
             throw new IllegalArgumentException("Only type BYTE_GRAY is supported");
         }
     }

     /**
      * <p>Writes a rectangular area of pixels in the destination <code>BufferedImage</code>. Calling this method on an
      * image of type different from <code>BufferedImage.TYPE_INT_ARGB</code> and <code>BufferedImage.TYPE_INT_RGB</code>
      * will unmanage the image.</p>
      *
      * @param img    the destination image
      * @param x      the x location at which to start storing pixels
      * @param y      the y location at which to start storing pixels
      * @param w      the width of the rectangle of pixels to store
      * @param h      the height of the rectangle of pixels to store
      * @param pixels an array of pixels, stored as integers
      * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h
      */
     static void setPixels(BufferedImage img,
                                  int x, int y, int w, int h, byte[] pixels) {
         if (pixels == null || w == 0 || h == 0) {
             return;
         } else if (pixels.length < w * h) {
             throw new IllegalArgumentException("pixels array must have a length >= w*h");
         }
         int imageType = img.getType();
         if (imageType == BufferedImage.TYPE_BYTE_GRAY) {
             WritableRaster raster = img.getRaster();
             raster.setDataElements(x, y, w, h, pixels);
         } else {
             throw new IllegalArgumentException("Only type BYTE_GRAY is supported");
         }
     }

     /**
      * <p>Returns an array of pixels, stored as integers, from a
      * <code>BufferedImage</code>. The pixels are grabbed from a rectangular
      * area defined by a location and two dimensions. Calling this method on
      * an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>
      * and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
      *
      * @param img the source image
      * @param x the x location at which to start grabbing pixels
      * @param y the y location at which to start grabbing pixels
      * @param w the width of the rectangle of pixels to grab
      * @param h the height of the rectangle of pixels to grab
      * @param pixels a pre-allocated array of pixels of size w*h; can be null
      * @return <code>pixels</code> if non-null, a new array of integers
      *   otherwise
      * @throws IllegalArgumentException is <code>pixels</code> is non-null and
      *   of length &lt; w*h
      */
     public static int[] getPixels(BufferedImage img,
                                   int x, int y, int w, int h, int[] pixels) {
         if (w == 0 || h == 0) {
             return new int[0];
         }

         if (pixels == null) {
             pixels = new int[w * h];
         } else if (pixels.length < w * h) {
             throw new IllegalArgumentException("pixels array must have a length" +
                                                " >= w*h");
         }

         int imageType = img.getType();
         if (imageType == BufferedImage.TYPE_INT_ARGB ||
             imageType == BufferedImage.TYPE_INT_RGB) {
             Raster raster = img.getRaster();
             return (int[]) raster.getDataElements(x, y, w, h, pixels);
         }

         // Unmanages the image
         return img.getRGB(x, y, w, h, pixels, 0, w);
     }

     /**
      * <p>Writes a rectangular area of pixels in the destination
      * <code>BufferedImage</code>. Calling this method on
      * an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>
      * and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
      *
      * @param img the destination image
      * @param x the x location at which to start storing pixels
      * @param y the y location at which to start storing pixels
      * @param w the width of the rectangle of pixels to store
      * @param h the height of the rectangle of pixels to store
      * @param pixels an array of pixels, stored as integers
      * @throws IllegalArgumentException is <code>pixels</code> is non-null and
      *   of length &lt; w*h
      */
     public static void setPixels(BufferedImage img,
                                  int x, int y, int w, int h, int[] pixels) {
         if (pixels == null || w == 0 || h == 0) {
             return;
         } else if (pixels.length < w * h) {
             throw new IllegalArgumentException("pixels array must have a length" +
                                                " >= w*h");
         }

         int imageType = img.getType();
         if (imageType == BufferedImage.TYPE_INT_ARGB ||
             imageType == BufferedImage.TYPE_INT_RGB) {
             WritableRaster raster = img.getRaster();
             raster.setDataElements(x, y, w, h, pixels);
         } else {
             // Unmanages the image
             img.setRGB(x, y, w, h, pixels, 0, w);
         }
     }

     /**
      * <p>Returns a new <code>BufferedImage</code> using the same color model
      * as the image passed as a parameter. The returned image is only compatible
      * with the image passed as a parameter. This does not mean the returned
      * image is compatible with the hardware.</p>
      *
      * @param image the reference image from which the color model of the new
      *   image is obtained
      * @return a new <code>BufferedImage</code>, compatible with the color model
      *   of <code>image</code>
      */
     public static BufferedImage createColorModelCompatibleImage(BufferedImage image) {
         ColorModel cm = image.getColorModel();
         return new BufferedImage(cm,
             cm.createCompatibleWritableRaster(image.getWidth(),
                                               image.getHeight()),
             cm.isAlphaPremultiplied(), null);
     }

     /**
      * <p>Returns a new translucent compatible image of the specified width and
      * height. That is, the returned <code>BufferedImage</code> is compatible with
      * the graphics hardware. If the method is called in a headless
      * environment, then the returned BufferedImage will be compatible with
      * the source image.</p>
      *
      * @param width the width of the new image
      * @param height the height of the new image
      * @return a new translucent compatible <code>BufferedImage</code> of the
      *   specified width and height
      */
     public static BufferedImage createCompatibleTranslucentImage(int width,
                                                                  int height) {
         return isHeadless() ?
                 new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB) :
                 getGraphicsConfiguration().createCompatibleImage(width, height,
                                                    Transparency.TRANSLUCENT);
     }

     private static boolean isHeadless() {
         return GraphicsEnvironment.isHeadless();
     }

     // Returns the graphics configuration for the primary screen
     private static GraphicsConfiguration getGraphicsConfiguration() {
         return GraphicsEnvironment.getLocalGraphicsEnvironment().
                     getDefaultScreenDevice().getDefaultConfiguration();
     }

 }
	/*
	* Copyright (c) 2005, 2006, 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.
	*/
	package javax.swing.plaf.nimbus;

	import java.awt.AlphaComposite;
	import java.awt.Graphics2D;
	import java.awt.Transparency;
	import java.awt.GraphicsConfiguration;
	import java.awt.GraphicsEnvironment;
	import java.awt.image.BufferedImage;
	import java.awt.image.Raster;
	import java.awt.image.WritableRaster;
	import java.awt.image.ColorModel;

	/**
	* EffectUtils
	*
	* @author Created by Jasper Potts (Jun 18, 2007)
	*/
	class EffectUtils {

	/**
	* Clear a transparent image to 100% transparent
	*
	* @param img The image to clear
	*/
	static void clearImage(BufferedImage img) {
	Graphics2D g2 = img.createGraphics();
	g2.setComposite(AlphaComposite.Clear);
	g2.fillRect(0, 0, img.getWidth(), img.getHeight());
	g2.dispose();
	}

	// =================================================================================================================
	// Blur

	/**
	* Apply Gaussian Blur to Image
	*
	* @param src The image tp
	* @param dst The destination image to draw blured src image into, null if you want a new one created
	* @param radius The blur kernel radius
	* @return The blured image
	*/
	static BufferedImage gaussianBlur(BufferedImage src, BufferedImage dst, int radius) {
	int width = src.getWidth();
	int height = src.getHeight();
	if (dst == null \|\| dst.getWidth() != width \|\| dst.getHeight() != height \|\| src.getType() != dst.getType()) {
	dst = createColorModelCompatibleImage(src);
	}
	float[] kernel = createGaussianKernel(radius);
	if (src.getType() == BufferedImage.TYPE_INT_ARGB) {
	int[] srcPixels = new int[width * height];
	int[] dstPixels = new int[width * height];
	getPixels(src, 0, 0, width, height, srcPixels);
	// horizontal pass
	blur(srcPixels, dstPixels, width, height, kernel, radius);
	// vertical pass
	//noinspection SuspiciousNameCombination
	blur(dstPixels, srcPixels, height, width, kernel, radius);
	// the result is now stored in srcPixels due to the 2nd pass
	setPixels(dst, 0, 0, width, height, srcPixels);
	} else if (src.getType() == BufferedImage.TYPE_BYTE_GRAY) {
	byte[] srcPixels = new byte[width * height];
	byte[] dstPixels = new byte[width * height];
	getPixels(src, 0, 0, width, height, srcPixels);
	// horizontal pass
	blur(srcPixels, dstPixels, width, height, kernel, radius);
	// vertical pass
	//noinspection SuspiciousNameCombination
	blur(dstPixels, srcPixels, height, width, kernel, radius);
	// the result is now stored in srcPixels due to the 2nd pass
	setPixels(dst, 0, 0, width, height, srcPixels);
	} else {
	throw new IllegalArgumentException("EffectUtils.gaussianBlur() src image is not a supported type, type=[" +
	src.getType() + "]");
	}
	return dst;
	}

	/**
	* <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by the radius which
	* must be greater than 0.</p> <p>The source and destination pixels arrays are expected to be in the INT_ARGB
	* format.</p> <p>After this method is executed, dstPixels contains a transposed and filtered copy of
	* srcPixels.</p>
	*
	* @param srcPixels the source pixels
	* @param dstPixels the destination pixels
	* @param width the width of the source picture
	* @param height the height of the source picture
	* @param kernel the kernel of the blur effect
	* @param radius the radius of the blur effect
	*/
	private static void blur(int[] srcPixels, int[] dstPixels,
	int width, int height,
	float[] kernel, int radius) {
	float a;
	float r;
	float g;
	float b;

	int ca;
	int cr;
	int cg;
	int cb;

	for (int y = 0; y < height; y++) {
	int index = y;
	int offset = y * width;

	for (int x = 0; x < width; x++) {
	a = r = g = b = 0.0f;

	for (int i = -radius; i <= radius; i++) {
	int subOffset = x + i;
	if (subOffset < 0 \|\| subOffset >= width) {
	subOffset = (x + width) % width;
	}

	int pixel = srcPixels[offset + subOffset];
	float blurFactor = kernel[radius + i];

	a += blurFactor * ((pixel >> 24) & 0xFF);
	r += blurFactor * ((pixel >> 16) & 0xFF);
	g += blurFactor * ((pixel >> 8) & 0xFF);
	b += blurFactor * ((pixel) & 0xFF);
	}

	ca = (int) (a + 0.5f);
	cr = (int) (r + 0.5f);
	cg = (int) (g + 0.5f);
	cb = (int) (b + 0.5f);

	dstPixels[index] = ((ca > 255 ? 255 : ca) << 24) \|
	((cr > 255 ? 255 : cr) << 16) \|
	((cg > 255 ? 255 : cg) << 8) \|
	(cb > 255 ? 255 : cb);
	index += height;
	}
	}
	}

	/**
	* <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by the radius which
	* must be greater than 0.</p> <p>The source and destination pixels arrays are expected to be in the BYTE_GREY
	* format.</p> <p>After this method is executed, dstPixels contains a transposed and filtered copy of
	* srcPixels.</p>
	*
	* @param srcPixels the source pixels
	* @param dstPixels the destination pixels
	* @param width the width of the source picture
	* @param height the height of the source picture
	* @param kernel the kernel of the blur effect
	* @param radius the radius of the blur effect
	*/
	static void blur(byte[] srcPixels, byte[] dstPixels,
	int width, int height,
	float[] kernel, int radius) {
	float p;
	int cp;
	for (int y = 0; y < height; y++) {
	int index = y;
	int offset = y * width;
	for (int x = 0; x < width; x++) {
	p = 0.0f;
	for (int i = -radius; i <= radius; i++) {
	int subOffset = x + i;
	// if (subOffset < 0) subOffset = 0;
	// if (subOffset >= width) subOffset = width-1;
	if (subOffset < 0 \|\| subOffset >= width) {
	subOffset = (x + width) % width;
	}
	int pixel = srcPixels[offset + subOffset] & 0xFF;
	float blurFactor = kernel[radius + i];
	p += blurFactor * pixel;
	}
	cp = (int) (p + 0.5f);
	dstPixels[index] = (byte) (cp > 255 ? 255 : cp);
	index += height;
	}
	}
	}

	static float[] createGaussianKernel(int radius) {
	if (radius < 1) {
	throw new IllegalArgumentException("Radius must be >= 1");
	}

	float[] data = new float[radius * 2 + 1];

	float sigma = radius / 3.0f;
	float twoSigmaSquare = 2.0f * sigma * sigma;
	float sigmaRoot = (float) Math.sqrt(twoSigmaSquare * Math.PI);
	float total = 0.0f;

	for (int i = -radius; i <= radius; i++) {
	float distance = i * i;
	int index = i + radius;
	data[index] = (float) Math.exp(-distance / twoSigmaSquare) / sigmaRoot;
	total += data[index];
	}

	for (int i = 0; i < data.length; i++) {
	data[i] /= total;
	}

	return data;
	}

	// =================================================================================================================
	// Get/Set Pixels helper methods

	/**
	* <p>Returns an array of pixels, stored as integers, from a <code>BufferedImage</code>. The pixels are grabbed from
	* a rectangular area defined by a location and two dimensions. Calling this method on an image of type different
	* from <code>BufferedImage.TYPE_INT_ARGB</code> and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the
	* image.</p>
	*
	* @param img the source image
	* @param x the x location at which to start grabbing pixels
	* @param y the y location at which to start grabbing pixels
	* @param w the width of the rectangle of pixels to grab
	* @param h the height of the rectangle of pixels to grab
	* @param pixels a pre-allocated array of pixels of size w*h; can be null
	* @return <code>pixels</code> if non-null, a new array of integers otherwise
	* @throws IllegalArgumentException is <code>pixels</code> is non-null and of length < w*h
	*/
	static byte[] getPixels(BufferedImage img,
	int x, int y, int w, int h, byte[] pixels) {
	if (w == 0 \|\| h == 0) {
	return new byte[0];
	}

	if (pixels == null) {
	pixels = new byte[w * h];
	} else if (pixels.length < w * h) {
	throw new IllegalArgumentException("pixels array must have a length >= w*h");
	}

	int imageType = img.getType();
	if (imageType == BufferedImage.TYPE_BYTE_GRAY) {
	Raster raster = img.getRaster();
	return (byte[]) raster.getDataElements(x, y, w, h, pixels);
	} else {
	throw new IllegalArgumentException("Only type BYTE_GRAY is supported");
	}
	}

	/**
	* <p>Writes a rectangular area of pixels in the destination <code>BufferedImage</code>. Calling this method on an
	* image of type different from <code>BufferedImage.TYPE_INT_ARGB</code> and <code>BufferedImage.TYPE_INT_RGB</code>
	* will unmanage the image.</p>
	*
	* @param img the destination image
	* @param x the x location at which to start storing pixels
	* @param y the y location at which to start storing pixels
	* @param w the width of the rectangle of pixels to store
	* @param h the height of the rectangle of pixels to store
	* @param pixels an array of pixels, stored as integers
	* @throws IllegalArgumentException is <code>pixels</code> is non-null and of length < w*h
	*/
	static void setPixels(BufferedImage img,
	int x, int y, int w, int h, byte[] pixels) {
	if (pixels == null \|\| w == 0 \|\| h == 0) {
	return;
	} else if (pixels.length < w * h) {
	throw new IllegalArgumentException("pixels array must have a length >= w*h");
	}
	int imageType = img.getType();
	if (imageType == BufferedImage.TYPE_BYTE_GRAY) {
	WritableRaster raster = img.getRaster();
	raster.setDataElements(x, y, w, h, pixels);
	} else {
	throw new IllegalArgumentException("Only type BYTE_GRAY is supported");
	}
	}

	/**
	* <p>Returns an array of pixels, stored as integers, from a
	* <code>BufferedImage</code>. The pixels are grabbed from a rectangular
	* area defined by a location and two dimensions. Calling this method on
	* an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>
	* and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
	*
	* @param img the source image
	* @param x the x location at which to start grabbing pixels
	* @param y the y location at which to start grabbing pixels
	* @param w the width of the rectangle of pixels to grab
	* @param h the height of the rectangle of pixels to grab
	* @param pixels a pre-allocated array of pixels of size w*h; can be null
	* @return <code>pixels</code> if non-null, a new array of integers
	* otherwise
	* @throws IllegalArgumentException is <code>pixels</code> is non-null and
	* of length < w*h
	*/
	public static int[] getPixels(BufferedImage img,
	int x, int y, int w, int h, int[] pixels) {
	if (w == 0 \|\| h == 0) {
	return new int[0];
	}

	if (pixels == null) {
	pixels = new int[w * h];
	} else if (pixels.length < w * h) {
	throw new IllegalArgumentException("pixels array must have a length" +
	" >= w*h");
	}

	int imageType = img.getType();
	if (imageType == BufferedImage.TYPE_INT_ARGB \|\|
	imageType == BufferedImage.TYPE_INT_RGB) {
	Raster raster = img.getRaster();
	return (int[]) raster.getDataElements(x, y, w, h, pixels);
	}

	// Unmanages the image
	return img.getRGB(x, y, w, h, pixels, 0, w);
	}

	/**
	* <p>Writes a rectangular area of pixels in the destination
	* <code>BufferedImage</code>. Calling this method on
	* an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>
	* and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
	*
	* @param img the destination image
	* @param x the x location at which to start storing pixels
	* @param y the y location at which to start storing pixels
	* @param w the width of the rectangle of pixels to store
	* @param h the height of the rectangle of pixels to store
	* @param pixels an array of pixels, stored as integers
	* @throws IllegalArgumentException is <code>pixels</code> is non-null and
	* of length < w*h
	*/
	public static void setPixels(BufferedImage img,
	int x, int y, int w, int h, int[] pixels) {
	if (pixels == null \|\| w == 0 \|\| h == 0) {
	return;
	} else if (pixels.length < w * h) {
	throw new IllegalArgumentException("pixels array must have a length" +
	" >= w*h");
	}

	int imageType = img.getType();
	if (imageType == BufferedImage.TYPE_INT_ARGB \|\|
	imageType == BufferedImage.TYPE_INT_RGB) {
	WritableRaster raster = img.getRaster();
	raster.setDataElements(x, y, w, h, pixels);
	} else {
	// Unmanages the image
	img.setRGB(x, y, w, h, pixels, 0, w);
	}
	}

	/**
	* <p>Returns a new <code>BufferedImage</code> using the same color model
	* as the image passed as a parameter. The returned image is only compatible
	* with the image passed as a parameter. This does not mean the returned
	* image is compatible with the hardware.</p>
	*
	* @param image the reference image from which the color model of the new
	* image is obtained
	* @return a new <code>BufferedImage</code>, compatible with the color model
	* of <code>image</code>
	*/
	public static BufferedImage createColorModelCompatibleImage(BufferedImage image) {
	ColorModel cm = image.getColorModel();
	return new BufferedImage(cm,
	cm.createCompatibleWritableRaster(image.getWidth(),
	image.getHeight()),
	cm.isAlphaPremultiplied(), null);
	}

	/**
	* <p>Returns a new translucent compatible image of the specified width and
	* height. That is, the returned <code>BufferedImage</code> is compatible with
	* the graphics hardware. If the method is called in a headless
	* environment, then the returned BufferedImage will be compatible with
	* the source image.</p>
	*
	* @param width the width of the new image
	* @param height the height of the new image
	* @return a new translucent compatible <code>BufferedImage</code> of the
	* specified width and height
	*/
	public static BufferedImage createCompatibleTranslucentImage(int width,
	int height) {
	return isHeadless() ?
	new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB) :
	getGraphicsConfiguration().createCompatibleImage(width, height,
	Transparency.TRANSLUCENT);
	}

	private static boolean isHeadless() {
	return GraphicsEnvironment.isHeadless();
	}

	// Returns the graphics configuration for the primary screen
	private static GraphicsConfiguration getGraphicsConfiguration() {
	return GraphicsEnvironment.getLocalGraphicsEnvironment().
	getDefaultScreenDevice().getDefaultConfiguration();
	}

	}