GlowFilter.java

/*
** Copyright 2005 Huxtable.com. All rights reserved.
*/

package com.jhlabs.image;

import java.awt.image.*;

/**
 * A filter which subtracts Gaussian blur from an image, sharpening it.
 * @author Jerry Huxtable
 */
public class GlowFilter extends GaussianFilter {

    static final long serialVersionUID = 5377089073023183684L;

    private float amount = 0.5f;
    
    public GlowFilter() {
        radius = 2;
    }
    
    public void setAmount( float amount ) {
        this.amount = amount;
    }
    
    public float getAmount() {
        return amount;
    }
    
    public BufferedImage filter( BufferedImage src, BufferedImage dst ) {
        int width = src.getWidth();
        int height = src.getHeight();

        if ( dst == null )
            dst = createCompatibleDestImage( src, null );

        int[] inPixels = new int[width*height];
        int[] outPixels = new int[width*height];
        src.getRGB( 0, 0, width, height, inPixels, 0, width );

        if ( radius > 0 ) {
            convolveAndTranspose(kernel, inPixels, outPixels, width, height, alpha, CLAMP_EDGES);
            convolveAndTranspose(kernel, outPixels, inPixels, height, width, alpha, CLAMP_EDGES);
        }

        src.getRGB( 0, 0, width, height, outPixels, 0, width );

        float a = 4*amount;

        int index = 0;
        for ( int y = 0; y < height; y++ ) {
            for ( int x = 0; x < width; x++ ) {
                int rgb1 = outPixels[index];
                int r1 = (rgb1 >> 16) & 0xff;
                int g1 = (rgb1 >> 8) & 0xff;
                int b1 = rgb1 & 0xff;

                int rgb2 = inPixels[index];
                int r2 = (rgb2 >> 16) & 0xff;
                int g2 = (rgb2 >> 8) & 0xff;
                int b2 = rgb2 & 0xff;

                r1 = PixelUtils.clamp( (int)(r1 + a * r2) );
                g1 = PixelUtils.clamp( (int)(g1 + a * g2) );
                b1 = PixelUtils.clamp( (int)(b1 + a * b2) );

                inPixels[index] = (rgb1 & 0xff000000) | (r1 << 16) | (g1 << 8) | b1;
                index++;
            }
        }

        dst.setRGB( 0, 0, width, height, inPixels, 0, width );
        return dst;
    }

    public String toString() {
        return "Blur/Glow...";
    }
}