/**
 *
 * Copyright (c) 2014, the Railo Company Ltd. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either 
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public 
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 * 
 **/
package lucee.runtime.img.composite;

import java.awt.CompositeContext;
import java.awt.RenderingHints;
import java.awt.image.ColorModel;

public final class AddComposite extends RGBComposite {

	public AddComposite( float alpha ) {
        super( alpha );
	}

	@Override
	public CompositeContext createContext( ColorModel srcColorModel, ColorModel dstColorModel, RenderingHints hints ) {
		return new Context( extraAlpha, srcColorModel, dstColorModel );
	}

    static class Context extends RGBCompositeContext {
        public Context( float alpha, ColorModel srcColorModel, ColorModel dstColorModel ) {
            super( alpha, srcColorModel, dstColorModel );
        }

        @Override
		public void composeRGB( int[] src, int[] dst, float alpha ) {
            int w = src.length;

            for ( int i = 0; i < w; i += 4 ) {
                int sr = src[i];
                int dir = dst[i];
                int sg = src[i+1];
                int dig = dst[i+1];
                int sb = src[i+2];
                int dib = dst[i+2];
                int sa = src[i+3];
                int dia = dst[i+3];
                int dor, dog, dob;

                dor = dir + sr;
                if ( dor > 255 )
                    dor = 255;
                dog = dig + sg;
                if ( dog > 255 )
                    dog = 255;
                dob = dib + sb;
                if ( dob > 255 )
                    dob = 255;

                float a = alpha*sa/255f;
                float ac = 1-a;

                dst[i] = (int)(a*dor + ac*dir);
                dst[i+1] = (int)(a*dog + ac*dig);
                dst[i+2] = (int)(a*dob + ac*dib);
                dst[i+3] = (int)(sa*alpha + dia*ac);
            }
        }
    }

}