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.Struct;
025    import railo.runtime.type.util.CollectionUtil;
026    
027    
028    
029    /**
030     * A filter which converts an image to grayscale using the NTSC brightness calculation.
031     */
032    public class GrayscaleFilter extends PointFilter  implements DynFiltering {
033    
034            public GrayscaleFilter() {
035                    canFilterIndexColorModel = true;
036            }
037    
038            public int filterRGB(int x, int y, int rgb) {
039                    int a = rgb & 0xff000000;
040                    int r = (rgb >> 16) & 0xff;
041                    int g = (rgb >> 8) & 0xff;
042                    int b = rgb & 0xff;
043    //              rgb = (r + g + b) / 3;  // simple average
044                    rgb = (r * 77 + g * 151 + b * 28) >> 8;   // NTSC luma
045                    return a | (rgb << 16) | (rgb << 8) | rgb;
046            }
047    
048            public String toString() {
049                    return "Colors/Grayscale";
050            }
051    
052            public BufferedImage filter(BufferedImage src, Struct parameters) throws PageException {BufferedImage dst=ImageUtil.createBufferedImage(src);
053                    Object o;
054                    if((o=parameters.removeEL(KeyImpl.init("Dimensions")))!=null){
055                            int[] dim=ImageFilterUtil.toDimensions(o,"Dimensions");
056                            setDimensions(dim[0],dim[1]);
057                    }
058    
059                    // check for arguments not supported
060                    if(parameters.size()>0) {
061                            throw new FunctionException(ThreadLocalPageContext.get(), "ImageFilter", 3, "parameters", "the parameter"+(parameters.size()>1?"s":"")+" ["+CollectionUtil.getKeyList(parameters,", ")+"] "+(parameters.size()>1?"are":"is")+" not allowed, only the following parameters are supported [Dimensions]");
062                    }
063    
064                    return filter(src, dst);
065            }
066    }
067    
068