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 unpremultiplies an image's alpha.
031     * Note: this does not change the image type of the BufferedImage
032     */
033    public class UnpremultiplyFilter extends PointFilter  implements DynFiltering {
034    
035            public UnpremultiplyFilter() {
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                    if ( a == 0 || a == 255 )
044                            return rgb;
045    
046                    float f = 255.0f / a;
047                    r *= f;
048                    g *= f;
049                    b *= f;
050                    if ( r > 255 )
051                            r = 255;
052                    if ( g > 255 )
053                            g = 255;
054                    if ( b > 255 )
055                            b = 255;
056                    return (a << 24) | (r << 16) | (g << 8) | b;
057            }
058    
059            public String toString() {
060                    return "Alpha/Unpremultiply";
061            }
062            public BufferedImage filter(BufferedImage src, Struct parameters) throws PageException {BufferedImage dst=ImageUtil.createBufferedImage(src);
063                    Object o;
064                    if((o=parameters.removeEL(KeyImpl.init("Dimensions")))!=null){
065                            int[] dim=ImageFilterUtil.toDimensions(o,"Dimensions");
066                            setDimensions(dim[0],dim[1]);
067                    }
068    
069                    // check for arguments not supported
070                    if(parameters.size()>0) {
071                            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]");
072                    }
073    
074                    return filter(src, dst);
075            }
076    }
077