package ie.dcu.swt;

import ie.dcu.image.colormap.*;
import ie.dcu.matrix.*;

import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.PaletteData;

/**
 * Visualize matrices using color maps.
 * 
 * @author Kevin McGuinness
 */
public class MatrixVisualizer {

	private ColorMap colorMap;
	
	public MatrixVisualizer() {
		this(ColorMaps.hot());
	}
	
	public MatrixVisualizer(ColorMap map) {
		setColorMap(map);
	}
	
	public ColorMap getColorMap() {
		return colorMap;
	}

	public void setColorMap(ColorMap map) {
		if (map == null) {
			throw new IllegalArgumentException("colorMap == null");
		}
		this.colorMap = map;
	}

	public ImageData createVisualization(Matrix matrix) {
		return visualize(matrix.toDoubleMatrix());
	}
	
	private ImageData visualize(DoubleMatrix matrix) {
		rescale(matrix);
		PaletteData palette = colorMap.createPaletteData();
		ImageData image = new ImageData(matrix.cols, matrix.rows, 8, palette);
		
		int n = colorMap.size();
		
		for (int i = 0; i < matrix.rows; i++) {
			int k = i * matrix.cols;

			for (int j = 0; j < matrix.cols; j++, k++) {
				int value = (int) (matrix.values[k] * (n-1));
				image.setPixel(j, i, value);
			}
		}
		
		return image;
	}
	
	private void rescale(DoubleMatrix matrix) {
		
		double min = matrix.minValue();
		double max = matrix.maxValue();
		double range = max - min;
		
		if (range == 0) {
			range = 1;
		}

		for (int i = 0; i < matrix.size; i++) {		
			matrix.values[i] = (matrix.values[i] + min) / range;
		}
	}
}