144 lines
5.2 KiB
Java
144 lines
5.2 KiB
Java
/* AlphaComposite.java -- provides a context for performing alpha compositing
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Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt;
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import java.awt.image.ColorModel;
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import java.util.LinkedHashMap;
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import java.util.Map;
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/**
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*
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* @author Eric Blake <ebb9@email.byu.edu>
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* @see Composite
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* @see CompositeContext
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* @since 1.3
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* @status updated to 1.4 except for createContext, needs documentation
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*/
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public final class AlphaComposite implements Composite
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{
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/** Map Long to AlphaComposites. See getInstance for details. */
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private static final LinkedHashMap cache = new LinkedHashMap(11, 0.75f, true)
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{
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/** The largest the alpha composite cache can grow. */
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private static final int MAX_CACHE_SIZE = 2048;
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/** Prune stale entries. */
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protected boolean removeEldestEntry(Map.Entry eldest)
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{ // XXX - FIXME Use Map.Entry, not just Entry as gcj 3.1 workaround.
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return size() > MAX_CACHE_SIZE;
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}
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};
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public static final int CLEAR = 1;
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public static final int SRC = 2;
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public static final int DST = 9;
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public static final int SRC_OVER = 3;
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public static final int DST_OVER = 4;
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public static final int SRC_IN = 5;
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public static final int DST_IN = 6;
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public static final int SRC_OUT = 7;
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public static final int DST_OUT = 8;
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public static final int SRC_ATOP = 10;
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public static final int DST_ATOP = 11;
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public static final int XOR = 12;
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public static final AlphaComposite Clear = getInstance(CLEAR);
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public static final AlphaComposite Src = getInstance(SRC);
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public static final AlphaComposite Dst = getInstance(DST);
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public static final AlphaComposite SrcOver = getInstance(SRC_OVER);
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public static final AlphaComposite DstOver = getInstance(DST_OVER);
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public static final AlphaComposite SrcIn = getInstance(SRC_IN);
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public static final AlphaComposite DstIn = getInstance(DST_IN);
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public static final AlphaComposite SrcOut = getInstance(SRC_OUT);
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public static final AlphaComposite DstOut = getInstance(DST_OUT);
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public static final AlphaComposite SrcAtop = getInstance(SRC_ATOP);
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public static final AlphaComposite DstAtop = getInstance(DST_ATOP);
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public static final AlphaComposite Xor = getInstance(XOR);
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private final int rule;
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private final float alpha;
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private AlphaComposite(int rule, float alpha)
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{
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this.rule = rule;
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this.alpha = alpha;
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}
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public static AlphaComposite getInstance(int rule)
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{
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return getInstance(rule, 1);
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}
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public static AlphaComposite getInstance(int rule, float alpha)
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{
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if (rule < CLEAR || rule > XOR || ! (alpha >= 0 && alpha <= 1))
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throw new IllegalArgumentException();
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// This long is guaranteed unique for all valid alpha composites.
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Long l = new Long(rule + Double.doubleToLongBits(alpha));
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AlphaComposite a = (AlphaComposite) cache.get(l);
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if (a == null)
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{
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a = new AlphaComposite(rule, alpha);
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cache.put(l, a);
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}
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return a;
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}
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public CompositeContext createContext(ColorModel srcColorModel,
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ColorModel dstColorModel,
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RenderingHints hints)
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{
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// XXX Implement. Sun uses undocumented implementation class
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// sun.java2d.SunCompositeContext.
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throw new Error("not implemented");
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}
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public float getAlpha()
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{
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return alpha;
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}
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public int getRule()
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{
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return rule;
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}
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public int hashCode()
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{
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return 31 * Float.floatToIntBits(alpha) + rule;
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}
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public boolean equals(Object o)
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{
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if (! (o instanceof AlphaComposite))
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return false;
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AlphaComposite a = (AlphaComposite) o;
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return rule == a.rule && alpha == a.alpha;
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}
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} // class AlphaComposite
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