001    /*
002    *
003    
004    Licensed under the Apache License, Version 2.0 (the "License");
005    you may not use this file except in compliance with the License.
006    You may obtain a copy of the License at
007    
008       http://www.apache.org/licenses/LICENSE-2.0
009    
010    Unless required by applicable law or agreed to in writing, software
011    distributed under the License is distributed on an "AS IS" BASIS,
012    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013    See the License for the specific language governing permissions and
014    limitations under the License.
015    */
016    
017    package railo.runtime.img.filter;import java.awt.image.BufferedImage;
018    
019    import railo.runtime.engine.ThreadLocalPageContext;
020    import railo.runtime.exp.FunctionException;
021    import railo.runtime.exp.PageException;
022    import railo.runtime.img.ImageUtil;
023    import railo.runtime.type.KeyImpl;
024    import railo.runtime.type.List;
025    import railo.runtime.type.Struct;
026    
027    
028    
029    /**
030     * A filter which premultiplies an image's alpha. 
031     * Note: this does not change the image type of the BufferedImage
032     */
033    public class PremultiplyFilter extends PointFilter  implements DynFiltering {
034    
035            public PremultiplyFilter() {
036            }
037    
038            public int filterRGB(int x, int y, int rgb) {
039                    int a = (rgb >> 24) & 0xff;
040                    int r = (rgb >> 16) & 0xff;
041                    int g = (rgb >> 8) & 0xff;
042                    int b = rgb & 0xff;
043                    float f = a * (1.0f / 255.0f);
044                    r *= f;
045                    g *= f;
046                    b *= f;
047                    return (a << 24) | (r << 16) | (g << 8) | b;
048            }
049    
050            public String toString() {
051                    return "Alpha/Premultiply";
052            }
053            public BufferedImage filter(BufferedImage src, Struct parameters) throws PageException {BufferedImage dst=ImageUtil.createBufferedImage(src);
054                    Object o;
055                    if((o=parameters.removeEL(KeyImpl.init("Dimensions")))!=null){
056                            int[] dim=ImageFilterUtil.toDimensions(o,"Dimensions");
057                            setDimensions(dim[0],dim[1]);
058                    }
059    
060                    // check for arguments not supported
061                    if(parameters.size()>0) {
062                            throw new FunctionException(ThreadLocalPageContext.get(), "ImageFilter", 3, "parameters", "the parameter"+(parameters.size()>1?"s":"")+" ["+List.arrayToList(parameters.keysAsString(),", ")+"] "+(parameters.size()>1?"are":"is")+" not allowed, only the following parameters are supported [Dimensions]");
063                    }
064    
065                    return filter(src, dst);
066            }
067    }
068