/**
 * 
 */
package neural;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;

public class ColorMap {

	/**
	 * @param data
	 * @param pixelsWidth
	 * @param pixelsHeight
	 * @return
	 * @throws Exception
	 * @see https://josetips.wordpress.com/category/java/
	 */
	public static BufferedImage generateImage(double[][] data, int pixelsWidth, int pixelsHeight) throws Exception {

		double x = 0, y = 0;
		BufferedImage bi = new BufferedImage(pixelsWidth, pixelsHeight, BufferedImage.TYPE_3BYTE_BGR);
		Graphics2D g = (Graphics2D) bi.getGraphics();

		int w = data[0].length;
		int l = data.length;
		double Dy = (double) pixelsHeight / (double) l;
		double Dx = (double) pixelsWidth / (double) w;
		int height = (int) Math.ceil(Dy);
		int width = (int) Math.ceil(Dx);
		int gap = (int) Math.ceil(width / 4);

		double max = -Double.MAX_VALUE;
		double min = Double.MAX_VALUE;
		for (int i = 0; i < l; i++) {
			for (int j = 0; j < w; j++) {
				max = data[i][j];
				if (data[i][j] < min) {
					min = data[i][j];
				}
			}
		}

		float fcolor;
		float saturation = (float) 0.9;
		float bright = (float) 0.7;

		g.setColor(Color.WHITE);
		g.fillRect(0, 0, pixelsWidth, pixelsHeight);
		for (int i = 0; i < l; i++) {
			for (int j = 0; j < w; j++) {
				fcolor = (float) ((data[i][j] - min) / (max - min));
				float hue = fcolor;
				g.setColor(Color.getHSBColor((float) (hue * 0.7), saturation, bright));
				g.fillRect((int) x, (int) y, width - gap, height);
				x += Dx;
			}
			y += Dy;
			x = 0;
		}

		File f = new File("color.png");
		try {
			ImageIO.write(bi, "png", f);
		}
		catch (IOException e) {
			e.printStackTrace();
		}
		g.dispose();

		return bi;
	}

	public static void main(String[] args) {
		double[][] data;
		int pixelsWidth = 300;
		int pixelsHeight = 400;
		Random r = new Random();

		data = new double[pixelsWidth][];
		for (int ndx = 0; ndx < pixelsWidth; ndx++) {
			data[ndx] = new double[pixelsHeight];
			for (int ndx2 = 0; ndx2 < pixelsHeight; ndx2++) {
//				data[ndx][ndx2] = r.nextDouble();
				 data[ndx][ndx2] = ndx2;
			}

		}

		try {
			generateImage(data, pixelsWidth, pixelsHeight);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

	}
}