001/*
002Copyright 2006 Jerry Huxtable
003
004Licensed under the Apache License, Version 2.0 (the "License");
005you may not use this file except in compliance with the License.
006You may obtain a copy of the License at
007
008   http://www.apache.org/licenses/LICENSE-2.0
009
010Unless required by applicable law or agreed to in writing, software
011distributed under the License is distributed on an "AS IS" BASIS,
012WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013See the License for the specific language governing permissions and
014limitations under the License.
015*/
016
017package com.jhlabs.image;
018
019import java.awt.image.*;
020
021/**
022 * A filter which adds Gaussian blur to an image, producing a glowing effect.
023 * @author Jerry Huxtable
024 */
025public class GlowFilter extends GaussianFilter {
026
027        private float amount = 0.5f;
028        
029        public GlowFilter() {
030                radius = 2;
031        }
032        
033        /**
034         * Set the amount of glow.
035         * @param amount the amount
036     * @min-value 0
037     * @max-value 1
038     * @see #getAmount
039         */
040        public void setAmount( float amount ) {
041                this.amount = amount;
042        }
043        
044        /**
045         * Get the amount of glow.
046         * @return the amount
047     * @see #setAmount
048         */
049        public float getAmount() {
050                return amount;
051        }
052        
053    public BufferedImage filter( BufferedImage src, BufferedImage dst ) {
054        int width = src.getWidth();
055        int height = src.getHeight();
056
057        if ( dst == null )
058            dst = createCompatibleDestImage( src, null );
059
060        int[] inPixels = new int[width*height];
061        int[] outPixels = new int[width*height];
062        src.getRGB( 0, 0, width, height, inPixels, 0, width );
063
064                if ( radius > 0 ) {
065                        convolveAndTranspose(kernel, inPixels, outPixels, width, height, alpha, alpha && premultiplyAlpha, false, CLAMP_EDGES);
066                        convolveAndTranspose(kernel, outPixels, inPixels, height, width, alpha, false, alpha && premultiplyAlpha, CLAMP_EDGES);
067                }
068
069        src.getRGB( 0, 0, width, height, outPixels, 0, width );
070
071                float a = 4*amount;
072
073                int index = 0;
074                for ( int y = 0; y < height; y++ ) {
075                        for ( int x = 0; x < width; x++ ) {
076                                int rgb1 = outPixels[index];
077                                int r1 = (rgb1 >> 16) & 0xff;
078                                int g1 = (rgb1 >> 8) & 0xff;
079                                int b1 = rgb1 & 0xff;
080
081                                int rgb2 = inPixels[index];
082                                int r2 = (rgb2 >> 16) & 0xff;
083                                int g2 = (rgb2 >> 8) & 0xff;
084                                int b2 = rgb2 & 0xff;
085
086                                r1 = PixelUtils.clamp( (int)(r1 + a * r2) );
087                                g1 = PixelUtils.clamp( (int)(g1 + a * g2) );
088                                b1 = PixelUtils.clamp( (int)(b1 + a * b2) );
089
090                                inPixels[index] = (rgb1 & 0xff000000) | (r1 << 16) | (g1 << 8) | b1;
091                                index++;
092                        }
093                }
094
095        dst.setRGB( 0, 0, width, height, inPixels, 0, width );
096        return dst;
097    }
098
099        public String toString() {
100                return "Blur/Glow...";
101        }
102}