org.jdesktop.swingx.image.GaussianBlurFilter Maven / Gradle / Ivy
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/*
* $Id: GaussianBlurFilter.java 1823 2007-03-15 15:08:03Z gfx $
*
* 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;
public class GaussianBlurFilter extends AbstractFilter {
private final int radius;
/**
* Creates a new blur filter with a default radius of 3.
*/
public GaussianBlurFilter() {
this(3);
}
/**
* Creates a new blur filter with the specified radius. If the radius
* is lower than 0, a radius of 0.1 will be used automatically.
*
* @param radius the radius, in pixels, of the blur
*/
public GaussianBlurFilter(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}
*/
@SuppressWarnings({ "SuspiciousNameCombination" })
@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];
float[] kernel = createGaussianKernel(radius);
GraphicsUtilities.getPixels(src, 0, 0, width, height, srcPixels);
// horizontal pass
blur(srcPixels, dstPixels, width, height, kernel, radius);
// vertical pass
blur(dstPixels, srcPixels, height, width, kernel, 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 kernel the kernel of the blur effect
* @param radius the radius of the blur effect
*/
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;
}
}
}
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;
}
}