fastgradientpaintcontext.java

java写的多功能文件编辑器

package com.incors.plaf;

/*
 * This code was contributed by Sebastian Ferreyra ([e-mail]).
 * It is published under the terms of the GNU Lesser General Public License.
 */

import java.awt.Color;
import java.awt.PaintContext;
import java.awt.Rectangle;
import java.awt.image.ColorModel;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.util.LinkedList;
import java.util.HashMap;
import java.util.WeakHashMap;

class FastGradientPaintContext implements PaintContext {
	private class GradientInfo {
		ColorModel model;
		int parallelLength, startColor, endColor;
		boolean isVertical;
		public boolean equals( Object o ) {
			if ( ! ( o instanceof GradientInfo ) ) return false;
			GradientInfo gi = (GradientInfo) o;
			if ( gi.model.equals(model) && gi.parallelLength == parallelLength && gi.startColor == startColor && gi.endColor == endColor && gi.isVertical == isVertical ) return true;
			return false;
		}
		public int hashCode() {
			return parallelLength;
		}
                public String toString() {
                    return "Direction:" + (isVertical?"ver":"hor") + ", Length: "+Integer.toString( parallelLength )+", Color1: "+Integer.toString( startColor, 16 )+", Color2: "+Integer.toString( endColor, 16 );
                }
	}

	private class Gradient {
		GradientInfo info;
		int perpendicularLength = 0;
		WritableRaster raster;
		HashMap childRasterCache;

		Gradient ( GradientInfo i ) { info = i; }

		private Raster getRaster( int parallelPos, int perpendicularLength, int parallelLength ) {
			if ( raster == null || ( this.perpendicularLength < perpendicularLength ) )  createRaster( perpendicularLength );

			Integer key = new Integer( parallelPos );
			Object o =  childRasterCache.get( key );
			if ( o !=null ) return (Raster) o;
			else {
				Raster r;
				if ( info.isVertical ) r = raster.createChild( 0, parallelPos, this.perpendicularLength, info.parallelLength-parallelPos, 0, 0, null );
				else r = raster.createChild( parallelPos, 0, info.parallelLength-parallelPos, this.perpendicularLength, 0, 0, null );
				childRasterCache.put( key, r );
                                //System.out.println( "Storing child raster in cache. Position: " + Integer.toString(parallelPos) );
				return r;
			}

		}

		public void dispose() {
//			raster = null;
		}

		private void createRaster( int perpendicularLength ) {
			int gradientWidth, gradientHeight;
			if ( info.isVertical ) {
				gradientHeight = info.parallelLength;
				gradientWidth = this.perpendicularLength = perpendicularLength;
			} else {
				gradientWidth = info.parallelLength;
				gradientHeight = this.perpendicularLength = perpendicularLength;
			}

			int sa =	(info.startColor >> 24)	& 0xFF;
			int sr =	(info.startColor >> 16)	& 0xFF;
			int sg =	(info.startColor >>  8)	& 0xFF;
			int sb =	info.startColor		& 0xFF;
			int da =	((info.endColor >> 24)	& 0xFF) - sa;
			int dr =	((info.endColor >> 16)	& 0xFF) - sr;
			int dg =	((info.endColor >>  8)	& 0xFF) - sg;
			int db =	(info.endColor		& 0xFF) - sb;

			raster = info.model.createCompatibleWritableRaster( gradientWidth, gradientHeight );

			Object c = null;
			int pl = info.parallelLength;
			for ( int i = 0 ; i < pl ; i++ ) {
				c = info.model.getDataElements( (sa+(i*da)/pl)<<24 | (sr+(i*dr)/pl)<<16 | (sg+(i*dg)/pl)<<8 | (sb+(i*db)/pl), c );
				for ( int j = 0 ; j < perpendicularLength ; j++ ) {
					if ( info.isVertical ) raster.setDataElements( j, i, c );
					else raster.setDataElements( i, j, c );
				}
			}
			childRasterCache = new HashMap();
		}
	}

	private static WeakHashMap gradientCache = new WeakHashMap();
        private static LinkedList recentInfos = new LinkedList();

	GradientInfo info;
	int parallelDevicePos;
	Gradient gradient;

	FastGradientPaintContext(ColorModel cm, Rectangle r, int sc, int ec, boolean ver ) {
		info = new GradientInfo();
		if ( (((sc & ec)>>24) & 0xFF) != 0xFF  ) info.model = ColorModel.getRGBdefault();
		else info.model = cm;
		info.startColor = sc;
		info.endColor = ec;
		if ( info.isVertical = ver ) {
			parallelDevicePos  = r.y;
			info.parallelLength = r.height;
		} else {
			parallelDevicePos = r.x;
			info.parallelLength = r.width;
		}
                recentInfos.remove( info );
                recentInfos.add( 0, info );
                if ( recentInfos.size() > 16 ) recentInfos.removeLast();
		Object o = gradientCache.get( info );
                if ( o != null ) o = ( ( java.lang.ref.WeakReference )o ).get();
		if ( o != null ) {
			gradient = (Gradient) o;
		} else {
			gradientCache.put( info, new java.lang.ref.WeakReference( gradient = new Gradient( info ) ) );
                        //System.out.println( "Storing gradient in cache. Info: " + info.toString() );
		}
	}

	public void dispose() {
		gradient.dispose();
	}

	public ColorModel getColorModel() {
		return info.model;
	}

	public synchronized Raster getRaster( int x, int y, int w, int h ) {
		if ( info.isVertical ) return gradient.getRaster( y - parallelDevicePos, w, h );
		else return gradient.getRaster( x - parallelDevicePos, h, w );
	}
}