001/** 002 * 003 * Copyright (c) 2014, the Railo Company Ltd. All rights reserved. 004 * 005 * This library is free software; you can redistribute it and/or 006 * modify it under the terms of the GNU Lesser General Public 007 * License as published by the Free Software Foundation; either 008 * version 2.1 of the License, or (at your option) any later version. 009 * 010 * This library is distributed in the hope that it will be useful, 011 * but WITHOUT ANY WARRANTY; without even the implied warranty of 012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 013 * Lesser General Public License for more details. 014 * 015 * You should have received a copy of the GNU Lesser General Public 016 * License along with this library. If not, see <http://www.gnu.org/licenses/>. 017 * 018 **/ 019 020package lucee.runtime.img.composite; 021 022import java.awt.CompositeContext; 023import java.awt.RenderingHints; 024import java.awt.image.ColorModel; 025 026public final class AverageComposite extends RGBComposite { 027 028 public AverageComposite( float alpha ) { 029 super( alpha ); 030 } 031 032 public CompositeContext createContext( ColorModel srcColorModel, ColorModel dstColorModel, RenderingHints hints ) { 033 return new Context( extraAlpha, srcColorModel, dstColorModel ); 034 } 035 036 static class Context extends RGBCompositeContext { 037 public Context( float alpha, ColorModel srcColorModel, ColorModel dstColorModel ) { 038 super( alpha, srcColorModel, dstColorModel ); 039 } 040 041 public void composeRGB( int[] src, int[] dst, float alpha ) { 042 int w = src.length; 043 044 for ( int i = 0; i < w; i += 4 ) { 045 int sr = src[i]; 046 int dir = dst[i]; 047 int sg = src[i+1]; 048 int dig = dst[i+1]; 049 int sb = src[i+2]; 050 int dib = dst[i+2]; 051 int sa = src[i+3]; 052 int dia = dst[i+3]; 053 int dor, dog, dob; 054 055 dor = (dir + sr) / 2; 056 dog = (dig + sg) / 2; 057 dob = (dib + sb) / 2; 058 059 float a = alpha*sa/255f; 060 float ac = 1-a; 061 062 dst[i] = (int)(a*dor + ac*dir); 063 dst[i+1] = (int)(a*dog + ac*dig); 064 dst[i+2] = (int)(a*dob + ac*dib); 065 dst[i+3] = (int)(sa*alpha + dia*ac); 066 } 067 } 068 } 069 070}