org.jdesktop.swingx.image.FastBlurFilter Maven / Gradle / Ivy
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/*
* $Id: FastBlurFilter.java 3742 2010-08-05 03:25:09Z kschaefe $
*
* Dual-licensed under LGPL (Sun and Romain Guy) and BSD (Romain Guy).
*
* Copyright 2006 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* Copyright (c) 2006 Romain Guy
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jdesktop.swingx.image;
import java.awt.image.BufferedImage;
import org.jdesktop.swingx.graphics.GraphicsUtilities;
/**
* A fast blur filter can be used to blur pictures quickly. This filter is an
* implementation of the box blur algorithm. The blurs generated by this
* algorithm might show square artifacts, especially on pictures containing
* straight lines (rectangles, text, etc.) On most pictures though, the
* result will look very good.
* The force of the blur can be controlled with a radius and the
* default radius is 3. Since the blur clamps values on the edges of the
* source picture, you might need to provide a picture with empty borders
* to avoid artifacts at the edges. The performance of this filter are
* independent from the radius.
*
* @author Romain Guy
*/
public class FastBlurFilter extends AbstractFilter {
private final int radius;
/**
* Creates a new blur filter with a default radius of 3.
*/
public FastBlurFilter() {
this(3);
}
/**
* Creates a new blur filter with the specified radius. If the radius
* is lower than 1, a radius of 1 will be used automatically.
*
* @param radius the radius, in pixels, of the blur
*/
public FastBlurFilter(int radius) {
if (radius < 1) {
radius = 1;
}
this.radius = radius;
}
/**
* Returns the radius used by this filter, in pixels.
*
* @return the radius of the blur
*/
public int getRadius() {
return radius;
}
/**
* {@inheritDoc}
*/
@Override
public BufferedImage filter(BufferedImage src, BufferedImage dst) {
int width = src.getWidth();
int height = src.getHeight();
if (dst == null) {
dst = createCompatibleDestImage(src, null);
}
int[] srcPixels = new int[width * height];
int[] dstPixels = new int[width * height];
GraphicsUtilities.getPixels(src, 0, 0, width, height, srcPixels);
// horizontal pass
blur(srcPixels, dstPixels, width, height, radius);
// vertical pass
//noinspection SuspiciousNameCombination
blur(dstPixels, srcPixels, height, width, radius);
// the result is now stored in srcPixels due to the 2nd pass
GraphicsUtilities.setPixels(dst, 0, 0, width, height, srcPixels);
return dst;
}
/**
* Blurs the source pixels into the destination pixels. The force of
* the blur is specified by the radius which must be greater than 0.
* The source and destination pixels arrays are expected to be in the
* INT_ARGB format.
* After this method is executed, dstPixels contains a transposed and
* filtered copy of srcPixels.
*
* @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 radius the radius of the blur effect
*/
static void blur(int[] srcPixels, int[] dstPixels,
int width, int height, int radius) {
final int windowSize = radius * 2 + 1;
final int radiusPlusOne = radius + 1;
int sumAlpha;
int sumRed;
int sumGreen;
int sumBlue;
int srcIndex = 0;
int dstIndex;
int pixel;
int[] sumLookupTable = new int[256 * windowSize];
for (int i = 0; i < sumLookupTable.length; i++) {
sumLookupTable[i] = i / windowSize;
}
int[] indexLookupTable = new int[radiusPlusOne];
if (radius < width) {
for (int i = 0; i < indexLookupTable.length; i++) {
indexLookupTable[i] = i;
}
} else {
for (int i = 0; i < width; i++) {
indexLookupTable[i] = i;
}
for (int i = width; i < indexLookupTable.length; i++) {
indexLookupTable[i] = width - 1;
}
}
for (int y = 0; y < height; y++) {
sumAlpha = sumRed = sumGreen = sumBlue = 0;
dstIndex = y;
pixel = srcPixels[srcIndex];
sumAlpha += radiusPlusOne * ((pixel >> 24) & 0xFF);
sumRed += radiusPlusOne * ((pixel >> 16) & 0xFF);
sumGreen += radiusPlusOne * ((pixel >> 8) & 0xFF);
sumBlue += radiusPlusOne * ( pixel & 0xFF);
for (int i = 1; i <= radius; i++) {
pixel = srcPixels[srcIndex + indexLookupTable[i]];
sumAlpha += (pixel >> 24) & 0xFF;
sumRed += (pixel >> 16) & 0xFF;
sumGreen += (pixel >> 8) & 0xFF;
sumBlue += pixel & 0xFF;
}
for (int x = 0; x < width; x++) {
dstPixels[dstIndex] = sumLookupTable[sumAlpha] << 24 |
sumLookupTable[sumRed] << 16 |
sumLookupTable[sumGreen] << 8 |
sumLookupTable[sumBlue];
dstIndex += height;
int nextPixelIndex = x + radiusPlusOne;
if (nextPixelIndex >= width) {
nextPixelIndex = width - 1;
}
int previousPixelIndex = x - radius;
if (previousPixelIndex < 0) {
previousPixelIndex = 0;
}
int nextPixel = srcPixels[srcIndex + nextPixelIndex];
int previousPixel = srcPixels[srcIndex + previousPixelIndex];
sumAlpha += (nextPixel >> 24) & 0xFF;
sumAlpha -= (previousPixel >> 24) & 0xFF;
sumRed += (nextPixel >> 16) & 0xFF;
sumRed -= (previousPixel >> 16) & 0xFF;
sumGreen += (nextPixel >> 8) & 0xFF;
sumGreen -= (previousPixel >> 8) & 0xFF;
sumBlue += nextPixel & 0xFF;
sumBlue -= previousPixel & 0xFF;
}
srcIndex += width;
}
}
}