little gui for testing the different blending functions of imagingkit

Blending Demo

	public static void main(String[] args) throws IOException {
		
		JPanel mainpanel = new JPanel();
		mainpanel.setLayout(new BorderLayout());
		ImagePanel imgpanel = new ImagePanel();
		imgpanel.setPreferredSize(new Dimension(200, 200));
		JComboBox<Blending> blendselector = new JComboBox<>(Blending.values());
		final JLabel renderlabel = new JLabel();
		blendselector.setRenderer((list,blend,idx,selected,focused)->{
			renderlabel.setText(blend.name());
			renderlabel.setBackground(selected?Color.gray:Color.lightGray);
			return renderlabel;
		});
		JSlider opacityslider = new JSlider(JSlider.HORIZONTAL, 0, 255, 255);
		JButton swapButton = new JButton("swap");
		mainpanel.add(imgpanel, BorderLayout.CENTER);
		mainpanel.add(blendselector, BorderLayout.SOUTH);
		mainpanel.add(opacityslider, BorderLayout.NORTH);
		mainpanel.add(swapButton, BorderLayout.EAST);
		
		Img img1 = loadImg("http://sipi.usc.edu/database/preview/misc/4.2.05.png");
		Img img2 = loadImg("http://sipi.usc.edu/database/preview/misc/4.2.06.png");
		Img renderImg = img1.copy();
		Img[] imgArray = {img1,img2};
		
		imgpanel.setImg(renderImg);
		int[] topIdx = {1};
		
		Runnable performBlending = () -> {
			int t = topIdx[0]%2;
			int b = (t+1)%2;
			Blending blend = (Blending) blendselector.getSelectedItem();
			float opacity = opacityslider.getValue()/(255.0f);
			imgArray[b].copyArea(0, 0, imgArray[b].getWidth(), imgArray[b].getHeight(), renderImg, 0, 0);
			renderImg.forEach(blend.getAlphaBlendingWith(imgArray[t],opacity));
			imgpanel.repaint();
		};
		blendselector.addActionListener((a)->{
			performBlending.run();
		});
		opacityslider.addChangeListener((e)->{
			performBlending.run();
		});
		swapButton.addActionListener((a)->{
			topIdx[0]++; performBlending.run();
		});
		
		
		JFrame frame = new JFrame("blending demo");
		frame.setContentPane(mainpanel);
		frame.pack();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
		performBlending.run();
	}
	
	static Img loadImg(String url) throws IOException{
		URL u = new URL(url);
		return Img.createRemoteImg(ImageLoader.loadImage(u.openStream(), BufferedImage.TYPE_INT_ARGB));
	}