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1: /* AlphaComposite.java -- provides a context for performing alpha compositing 2: Copyright (C) 2002, 2005 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package java.awt; 40: 41: import java.awt.image.ColorModel; 42: import java.util.LinkedHashMap; 43: import java.util.Map; 44: 45: /** 46: * 47: * @author Eric Blake (ebb9@email.byu.edu) 48: * @see Composite 49: * @see CompositeContext 50: * @since 1.3 51: * @status updated to 1.4 except for createContext, needs documentation 52: */ 53: public final class AlphaComposite implements Composite 54: { 55: /** Map Long to AlphaComposites. See getInstance for details. */ 56: private static final LinkedHashMap cache = new LinkedHashMap(11, 0.75f, true) 57: { 58: /** The largest the alpha composite cache can grow. */ 59: private static final int MAX_CACHE_SIZE = 2048; 60: 61: /** Prune stale entries. */ 62: protected boolean removeEldestEntry(Map.Entry eldest) 63: { // XXX - FIXME Use Map.Entry, not just Entry as gcj 3.1 workaround. 64: return size() > MAX_CACHE_SIZE; 65: } 66: }; 67: 68: public static final int CLEAR = 1; 69: public static final int SRC = 2; 70: public static final int DST = 9; 71: public static final int SRC_OVER = 3; 72: public static final int DST_OVER = 4; 73: public static final int SRC_IN = 5; 74: public static final int DST_IN = 6; 75: public static final int SRC_OUT = 7; 76: public static final int DST_OUT = 8; 77: public static final int SRC_ATOP = 10; 78: public static final int DST_ATOP = 11; 79: public static final int XOR = 12; 80: public static final AlphaComposite Clear = getInstance(CLEAR); 81: public static final AlphaComposite Src = getInstance(SRC); 82: public static final AlphaComposite Dst = getInstance(DST); 83: public static final AlphaComposite SrcOver = getInstance(SRC_OVER); 84: public static final AlphaComposite DstOver = getInstance(DST_OVER); 85: public static final AlphaComposite SrcIn = getInstance(SRC_IN); 86: public static final AlphaComposite DstIn = getInstance(DST_IN); 87: public static final AlphaComposite SrcOut = getInstance(SRC_OUT); 88: public static final AlphaComposite DstOut = getInstance(DST_OUT); 89: public static final AlphaComposite SrcAtop = getInstance(SRC_ATOP); 90: public static final AlphaComposite DstAtop = getInstance(DST_ATOP); 91: public static final AlphaComposite Xor = getInstance(XOR); 92: 93: private final int rule; 94: private final float alpha; 95: private AlphaComposite(int rule, float alpha) 96: { 97: this.rule = rule; 98: this.alpha = alpha; 99: } 100: 101: /** 102: * Creates an AlphaComposite object with the specified rule. 103: * 104: * @param rule The compositing rule. 105: * 106: * @exception IllegalArgumentException If rule is not one of the following: 107: * CLEAR, SRC, DST, SRC_OVER, DST_OVER, SRC_IN, DST_IN, SRC_OUT, DST_OUT, 108: * SRC_ATOP, DST_ATOP, or XOR. 109: */ 110: public static AlphaComposite getInstance(int rule) 111: { 112: return getInstance(rule, 1); 113: } 114: 115: /** 116: * Creates an AlphaComposite object with the specified rule and the constant 117: * alpha to multiply with the alpha of the source. The source is multiplied 118: * with the specified alpha before being composited with the destination. 119: * 120: * @param rule The compositing rule. 121: * 122: * @exception IllegalArgumentException If rule is not one of the following: 123: * CLEAR, SRC, DST, SRC_OVER, DST_OVER, SRC_IN, DST_IN, SRC_OUT, DST_OUT, 124: * SRC_ATOP, DST_ATOP, or XOR. 125: */ 126: public static AlphaComposite getInstance(int rule, float alpha) 127: { 128: if (rule < CLEAR || rule > XOR || ! (alpha >= 0 && alpha <= 1)) 129: throw new IllegalArgumentException(); 130: // This long is guaranteed unique for all valid alpha composites. 131: Long l = new Long(rule + Double.doubleToLongBits(alpha)); 132: AlphaComposite a = (AlphaComposite) cache.get(l); 133: if (a == null) 134: { 135: a = new AlphaComposite(rule, alpha); 136: cache.put(l, a); 137: } 138: return a; 139: } 140: public CompositeContext createContext(ColorModel srcColorModel, 141: ColorModel dstColorModel, 142: RenderingHints hints) 143: { 144: // XXX Implement. Sun uses undocumented implementation class 145: // sun.java2d.SunCompositeContext. 146: throw new Error("not implemented"); 147: } 148: public float getAlpha() 149: { 150: return alpha; 151: } 152: public int getRule() 153: { 154: return rule; 155: } 156: public int hashCode() 157: { 158: return 31 * Float.floatToIntBits(alpha) + rule; 159: } 160: public boolean equals(Object o) 161: { 162: if (! (o instanceof AlphaComposite)) 163: return false; 164: AlphaComposite a = (AlphaComposite) o; 165: return rule == a.rule && alpha == a.alpha; 166: } 167: } // class AlphaComposite
GNU Classpath (0.20) |