[OpenJDK 2D-Dev] 6603887: Where are transparent areas filled with bgColor?

[Clemens Eisserer]

Hi Dimitri,

I hope the test fits your/the needs, I was not able to produce an
image that triggers the problem so I simply used the graybox_error.gif
- it does not contain black (which the uninitialized areas are
painted) so I can simply check for that.
However it depends one some assumptions (VI is accalerated, blitting
two times leads to accaleration, ??).

lg Clemens
Thanks for open-sourcing java :)

The test:
import java.awt.*;
import java.awt.image.*;

import javax.swing.*;

public class BgRegTest
{
	public static void main(String[] args)
	{
		JFrame testFrame = new JFrame();
		testFrame.setVisible(true);

		/*
		 * Set up images:
		 * 1.) VolatileImge for rendering to,
		 * 2.) BufferedImage for reading back the contents of the VI
		 * 3.) The image triggering the problem
		 */
		VolatileImage vImg = null;
		BufferedImage readBackBImg = new BufferedImage(25, 25,
BufferedImage.TYPE_INT_RGB);
		Image tImg = new
ImageIcon(testFrame.getClass().getResource("/graybox_error.gif")).getImage();
		Graphics readBackG = readBackBImg.getGraphics();

		do
		{
			if (vImg == null ||
vImg.validate(testFrame.getGraphicsConfiguration()) ==
VolatileImage.IMAGE_INCOMPATIBLE)
			{
				vImg = testFrame.createVolatileImage(25, 25);
			}

			Graphics viG = vImg.getGraphics();
			viG.setColor(Color.white);
			viG.fillRect(0, 0, 25, 25);
			//Blit it at least two times to make sure it becomes accalerated -
This is an assumption and may break if implementation changes
			viG.drawImage(tImg, 0, 0, Color.white, testFrame);
			viG.drawImage(tImg, 0, 0, Color.white, testFrame);

			readBackG.drawImage(vImg, 0, 0, testFrame);
		} while (vImg.contentsLost());

		//Check wether un-initialized pixels (black) exist
		for (int x = 0; x < readBackBImg.getWidth(); x++)
		{
			for (int y = 0; y < readBackBImg.getHeight(); y++)
			{
				int currPixel = readBackBImg.getRGB(x, y);
				if (currPixel == Color.black.getRGB())
				{
					throw new RuntimeException("Background has changed!");
				}
			}
		}
	}
}