effectutils.java

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/*
 * @(#)EffectUtils.java	1.2 07/12/12
 *
 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package com.sun.java.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)
 * @version 1.0
 */
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];