AlphaDepthCompositeContext.java

/*******************************************************************************
 * Breakout Cave Survey Visualizer
 *
 * Copyright (C) 2014 James Edwards
 *
 * jedwards8 at fastmail dot fm
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *******************************************************************************/
package com.andork.plot;

import java.awt.CompositeContext;
import java.awt.Rectangle;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;

public class AlphaDepthCompositeContext implements CompositeContext {
	@Override
	public void compose(Raster src, Raster dstIn, WritableRaster dstOut) {
		Rectangle r = src.getBounds();
		r = r.intersection(dstIn.getBounds());
		r = r.intersection(dstOut.getBounds());

		int[] srcPixels = src.getPixels(r.x, r.y, r.width, r.height, (int[]) null);
		int[] dstPixels = dstIn.getPixels(r.x, r.y, r.width, r.height, (int[]) null);

		for (int i = 0; i < srcPixels.length; i++) {
			int srcAlpha = srcPixels[i] >> 24;
			int dstAlpha = dstPixels[i] >> 24;

			dstPixels[i] = dstAlpha >= srcAlpha ? dstPixels[i] : srcPixels[i];
		}

		dstOut.setPixels(r.x, r.y, r.width, r.height, dstPixels);
	}

	@Override
	public void dispose() {

	}
}