Simple Java/SWT class for image sprites. Quickly slice up a larger image into smaller ones, while preserving alpha transparency. Most of the existing examples out there don't handle alphas properly.

SwtImageSprite.java

package com.andyhawkes.gists;
 
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;
 
/**
 * Simple class that demonstrates how to slice up regions of a sprite image in SWT, while preserving
 * alpha transparency. There are shorter ways to do this if you don't care about alpha transparency.
 */
public class SwtImageSprite {
    private Image sprite;
 
    public SwtImageSprite(Image sprite) {
        this.sprite = sprite;
    }
 
    public Image loadImageFromRegion(Rectangle region) {
        ImageData data = new ImageData(region.width, region.height, sprite.getImageData().depth, sprite.getImageData().palette);
    	int[] pixels = new int[region.width];
    	byte[] alphas = new byte[region.width];
    
    	for (int y = 0; y < region.height; y++) {
    		sprite.getImageData().getAlphas(region.x, region.y + y, region.width, alphas, 0);
    		sprite.getImageData().getPixels(region.x, region.y + y, region.width, pixels, 0);
    
    		data.setPixels(0, y, region.width, pixels, 0);
    		data.setAlphas(0, y, region.width, alphas, 0);
    	}
    
    	return new Image(Display.getCurrent(), data);
    }
}