package org.jzy3d.plot3d.builder.concrete;

import java.awt.image.BufferedImage;

import org.jzy3d.maths.Rectangle;
import org.jzy3d.plot3d.builder.Mapper;

/**
 * Mapper which reads height information from the grayscale
 * values of a BufferedImage, normalized to range [0..1].
 * 
 * @author Nils Hoffmann
 */
public class BufferedImageMapper extends Mapper {

    private final BufferedImage image;
    private final int maxRow;
    private final Rectangle maxViewPort;

    public BufferedImageMapper(BufferedImage bi) {
        this.image = bi;
        this.maxRow = this.image.getHeight() - 1;
        this.maxViewPort = new Rectangle(0, 0, bi.getWidth(), bi.getHeight());
    }

    /**
     * Returns the intersection of this BufferedImage's dimensions
     * with those passed in in Rectangle roi, if there is one. Otherwise,
     * the returned rectangle may be empty.
     * @param roi
     * @return
     */
    public Rectangle getClippedViewport(Rectangle roi) {
        return this.maxViewPort.intersection(roi);
    }

    @Override
public double f(double x, double y) {
    if (x == Double.NaN || y == Double.NaN) {
        return Double.NaN;
    }
    int rbg = image.getRGB((int) x, (maxRow) - ((int) y));
    float red = ((rbg >> 16) & 0xFF) / 255.0f;
    float green = ((rbg >> 8) & 0xFF) / 255.0f;
    float blue = ((rbg) & 0xFF) / 255.0f;
    return ((red * 0.3f) + (green * 0.59f) + (blue * 0.11f));
}
}