package ie.dcu.segment.painters;

import ie.dcu.segment.*;
import ie.dcu.swt.ObservableImage;

import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

/**
 * Shows the current segmentation mask
 * 
 * @author Kevin McGuinness
 */
public class MaskPainter implements SegmentationPainter {
	public static final String NAME = "Mask";

	private ImageData maskData;
	private Image maskImage;

	public String getDescription() {
		return "Shows the current segmentation mask";
	}


	public String getName() {
		return NAME;
	}
	
	public ImageData getMaskData(SegmentationContext ctx) {
		return maskData;
	}

	public void paint(SegmentationContext ctx, ObservableImage im) {

		GC gc = im.beginPaint();
		
		// Paint mask
		createVisibleMask(ctx.getMask());
		gc.drawImage(maskImage, 0, 0);

		// Commit changes
		im.endPaint();
	}
	
	
	private void createVisibleMask(SegmentationMask mask) {
		dispose();
		
		// Check if we have a compatible buffer
		if (isNewMaskDataRequired(mask.getBounds())) {
			maskData = createMaskData(mask.getBounds());
		} 
		
		// Blit in pixels
		for (int y = 0; y < mask.height; y++) {
			int maskOffset = y * mask.width;
			int dataOffset = y * maskData.bytesPerLine;
			System.arraycopy(mask.values, maskOffset, maskData.data, dataOffset, mask.width);
		}
		
		// Create new mask
		maskImage = new Image(Display.getCurrent(), maskData);
	}
	
	private boolean isNewMaskDataRequired(Rectangle bounds) {
		if (maskData == null) {
			return true;
		} else {
			return maskData.width != bounds.width || maskData.height != bounds.height;
		}
	}
	
	
	private static ImageData createMaskData(Rectangle bounds) {
		RGB[] colors = new RGB[] {
			new RGB(128,128,128),
			new RGB(255,255,255),
			new RGB(0, 0, 0)
		};
		
		// Create 3 color indexed palette
		PaletteData palette = new PaletteData(colors);
		
		// Create 8 bit indexed image
		ImageData data = new ImageData(bounds.width, bounds.height, 8, palette);
		
		// Create and return the image
		return data;
	}


	public void dispose() {
		/// Dispose mask
		if (maskImage != null) {
			if (!maskImage.isDisposed()) {
				maskImage.dispose();
			}
			maskImage = null;
		}
	}
}