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/*
* Copyright (c) 2010?? 2013?? Oracle and/or its affiliates. All rights reserved.
*
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* are met:
*
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*     notice?? this list of conditions and the following disclaimer.
*
*   - Redistributions in binary form must reproduce the above copyright
*     notice?? this list of conditions and the following disclaimer in the
*     documentation and/or other materials provided with the distribution.
*
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*     from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES?? INCLUDING?? BUT NOT LIMITED TO??
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* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT?? INDIRECT?? INCIDENTAL?? SPECIAL??
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*/
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;
import javax.imageio.ImageIO;
/**
* ForkBlur implements a simple horizontal image blur. It averages pixels in the
* source array and writes them to a destination array. The sThreshold value
* determines whether the blurring will be performed directly or split into two
* tasks.
*
* This is not the recommended way to blur images; it is only intended to
* illustrate the use of the Fork/Join framework.
*/
public class ForkBlur extends RecursiveAction {
private static final long serialVersionUID = -8032915917030559798L;
private int[] mSource;
private int mStart;
private int mLength;
private int[] mDestination;
private int mBlurWidth = 15; // Processing window size?? should be odd.
public ForkBlur(int[] src?? int start?? int length?? int[] dst) {
mSource = src;
mStart = start;
mLength = length;
mDestination = dst;
}
// Average pixels from source?? write results into destination.
protected void computeDirectly() {
int sidePixels = (mBlurWidth - 1) / 2;
for (int index = mStart; index < mStart + mLength; index++) {
// Calculate average.
float rt = 0?? gt = 0?? bt = 0;
for (int mi = -sidePixels; mi <= sidePixels; mi++) {
int mindex = Math.min(Math.max(mi + index?? 0)?? mSource.length - 1);
int pixel = mSource[mindex];
rt += (float) ((pixel & 0x00ff0000) >> 16) / mBlurWidth;
gt += (float) ((pixel & 0x0000ff00) >> 8) / mBlurWidth;
bt += (float) ((pixel & 0x000000ff) >> 0) / mBlurWidth;
}
// Re-assemble destination pixel.
int dpixel = (0xff000000)
| (((int) rt) << 16)
| (((int) gt) << 8)
| (((int) bt) << 0);
mDestination[index] = dpixel;
}
}
protected static int sThreshold = 10000;
@Override
protected void compute() {
if (mLength < sThreshold) {
computeDirectly();
return;
}
int split = mLength / 2;
invokeAll(new ForkBlur(mSource?? mStart?? split?? mDestination)??
new ForkBlur(mSource?? mStart + split?? mLength - split??
mDestination));
}
// Plumbing follows.
public static void main(String[] args) throws Exception {
String srcName = "C:\test6.jpg";
File srcFile = new File(srcName);
BufferedImage image = ImageIO.read(srcFile);
System.out.println("Source image: " + srcName);
BufferedImage blurredImage = blur(image);
String dstName = "C:\test6_out.jpg";
File dstFile = new File(dstName);
ImageIO.write(blurredImage?? "jpg"?? dstFile);
System.out.println("Output image: " + dstName);
}
public static BufferedImage blur(BufferedImage srcImage) {
int w = srcImage.getWidth();
int h = srcImage.getHeight();
int[] src = srcImage.getRGB(0?? 0?? w?? h?? null?? 0?? w);
int[] dst = new int[src.length];
System.out.println("Array size is " + src.length);
System.out.println("Threshold is " + sThreshold);
int processors = Runtime.getRuntime().availableProcessors();
System.out.println(Integer.toString(processors) + " processor"
+ (processors != 1 ? "s are " : " is ")
+ "available");
ForkBlur fb = new ForkBlur(src?? 0?? src.length?? dst);
ForkJoinPool pool = new ForkJoinPool();
long startTime = System.currentTimeMillis();
pool.invoke(fb);
long endTime = System.currentTimeMillis();
System.out.println("Image blur took " + (endTime - startTime) +
" milliseconds.");
BufferedImage dstImage =
new BufferedImage(w?? h?? BufferedImage.TYPE_INT_ARGB);
dstImage.setRGB(0?? 0?? w?? h?? dst?? 0?? w);
return dstImage;
}
}
????????????￡????Ч?????￡?
????Source image: C: est6.jpg
????Array size is 120000
????Threshold is 10000
????4 processors are available
????Image blur took 10 milliseconds.
????Output image: C: est6_out.jpg

????JDK?????fork/join??????
???????????????????????fork/join????????????????????????JAVA SE?У?????????fork/join?????????Щ???????????????????????????JAVA SE8 ??java.util.Arrays ???parallelSort()????????Щ??????sort()???????????????????fork/join????????С??????????????????????????У???ò??????????????????????Ч?????????????Щ???????????????fork/join?????????????????Χ??????????????JAVA API?????