package ie.dcu.swt;

import java.util.*;

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

/**
 * Create cursors.
 * 
 * @author Kevin McGuinness
 */
public class CursorFactory {
		
	/**
	 * Create a cross-hair cursor.
	 * 
	 * @return The newly created cursor.
	 */
	public static Cursor createCrosshairCursor() {
		
		// Size of cursor
		final int s = 24;
		
		// Number of points in cursor
		final int n = s*s;
		
		// Midpoint of cursor
		final int m = s/2;
		
		// Color indices
		final byte black = 1;
		final byte light = 2;
		final byte trans = 0;
		
		// Cursor array
		byte[] cursor = new byte[n];
		
		// Flood with transparency
		Arrays.fill(cursor, (byte) 0);
		
		// Set crosshair pixels
		for (int i = 0; i < s; i++) {
			
			// Choose color
			byte color = (i == m-2 || i == m+2) ? light : black;
						
			// Set pixels
			if (i < m-1 || i > m+1) {	
				int idx1 = i+m*s;
				int idx2 = m+i*s;
				cursor[idx1] = (byte) color;
				cursor[idx2] = (byte) color;
			} 
		}
		
		// Set center pixel
		cursor[m+m*s] = black;
		
		// Create colors
		RGB[] colors = new RGB[] { 
				new RGB(255,255,255), 
				new RGB(0,0,0),
				new RGB(128,128,128)
		};
		
		// Create palette
		PaletteData palette = new PaletteData(colors);
		
		// Create image
		ImageData image = new ImageData(s, s, 4, palette);
		image.transparentPixel = trans;
		image.setPixels(0, 0, n, cursor, 0);
		
		// Create cursor
		return new Cursor(Display.getCurrent(), image, s/2, s/2);
	}
}