/*
Copyright 2006 Jerry Huxtable

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package org.meteoinfo.image.filter;

import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;

/**
 * A filter which interpolates betwen two images. You can set the interpolation factor outside the range 0 to 1
 * to extrapolate images.
 */
public class InterpolateFilter extends AbstractBufferedImageOp {
	
	private BufferedImage destination;
	private float interpolation;

	public InterpolateFilter() {
	}

    /**
     * Set the destination image.
     * @param destination the destination image
     * @see #getDestination
     */
	public void setDestination( BufferedImage destination ) {
		this.destination = destination;
	}
	
    /**
     * Get the destination image.
     * @return the destination image
     * @see #setDestination
     */
	public BufferedImage getDestination() {
		return destination;
	}
	
    /**
     * Set the interpolation factor.
     * @param interpolation the interpolation factor
     * @see #getInterpolation
     */
	public void setInterpolation( float interpolation ) {
		this.interpolation = interpolation;
	}
	
    /**
     * Get the interpolation factor.
     * @return the interpolation factor
     * @see #setInterpolation
     */
	public float getInterpolation() {
		return interpolation;
	}
	
    public BufferedImage filter( BufferedImage src, BufferedImage dst ) {
        int width = src.getWidth();
        int height = src.getHeight();
		int type = src.getType();
		WritableRaster srcRaster = src.getRaster();

        if ( dst == null )
            dst = createCompatibleDestImage( src, null );
		WritableRaster dstRaster = dst.getRaster();

        if ( destination != null ) {
			width = Math.min( width, destination.getWidth() );
			height = Math.min( height, destination.getWidth() );
			int[] pixels1 = null;
			int[] pixels2 = null;

			for (int y = 0; y < height; y++) {
				pixels1 = getRGB( src, 0, y, width, 1, pixels1 );
				pixels2 = getRGB( destination, 0, y, width, 1, pixels2 );
				for (int x = 0; x < width; x++) {
					int rgb1 = pixels1[x];
					int rgb2 = pixels2[x];
					int a1 = (rgb1 >> 24) & 0xff;
					int r1 = (rgb1 >> 16) & 0xff;
					int g1 = (rgb1 >> 8) & 0xff;
					int b1 = rgb1 & 0xff;
					int a2 = (rgb2 >> 24) & 0xff;
					int r2 = (rgb2 >> 16) & 0xff;
					int g2 = (rgb2 >> 8) & 0xff;
					int b2 = rgb2 & 0xff;
					r1 = PixelUtils.clamp( ImageMath.lerp( interpolation, r1, r2 ) );
					g1 = PixelUtils.clamp( ImageMath.lerp( interpolation, g1, g2 ) );
					b1 = PixelUtils.clamp( ImageMath.lerp( interpolation, b1, b2 ) );
					pixels1[x] = (a1 << 24) | (r1 << 16) | (g1 << 8) | b1;
				}
				setRGB( dst, 0, y, width, 1, pixels1 );
			}
        }

        return dst;
    }

	public String toString() {
		return "Effects/Interpolate...";
	}
}
