/* @test
   @bug 6683775 6794764
   @summary Painting artifacts is seen when panel is made setOpaque(false) for a translucent window
   @author Alexander Potochkin
   @run main bug6683775
*/

import com.sun.awt.AWTUtilities;
import sun.awt.SunToolkit;

import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;

public class bug6683775 {
    public static void main(String[] args) throws Exception {
        GraphicsConfiguration gc = getGC();
        if (!AWTUtilities.isTranslucencySupported(
                AWTUtilities.Translucency.PERPIXEL_TRANSLUCENT)
                || gc == null) {
            return;
        }
        SunToolkit toolkit = (SunToolkit) Toolkit.getDefaultToolkit();
        Robot robot = new Robot();
        final JFrame testFrame = new JFrame(gc);

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame backgroundFrame = new JFrame("Background frame");
                backgroundFrame.setUndecorated(true);
                JPanel panel = new JPanel();
                panel.setBackground(Color.RED);
                backgroundFrame.add(panel);
                backgroundFrame.setSize(200, 200);
                backgroundFrame.setVisible(true);

                testFrame.setUndecorated(true);
                JPanel p = new JPanel();
                p.setOpaque(false);
                testFrame.add(p);
                AWTUtilities.setWindowOpaque(testFrame, false);
                testFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                testFrame.setSize(400, 400);
                testFrame.setLocation(0, 0);
                testFrame.setVisible(true);
            }
        });

        toolkit.realSync();

        //robot.getPixelColor() didn't work right for some reason
        BufferedImage capture = robot.createScreenCapture(new Rectangle(100, 100));

        int redRGB = Color.RED.getRGB();
        if (redRGB != capture.getRGB(10, 10)) {
            throw new RuntimeException("Transparent frame is not transparent!");
        }
    }

    private static GraphicsConfiguration getGC() {
        GraphicsConfiguration transparencyCapableGC =
                GraphicsEnvironment.getLocalGraphicsEnvironment()
                        .getDefaultScreenDevice().getDefaultConfiguration();
        if (!AWTUtilities.isTranslucencyCapable(transparencyCapableGC)) {
            transparencyCapableGC = null;

            GraphicsEnvironment env =
                    GraphicsEnvironment.getLocalGraphicsEnvironment();
            GraphicsDevice[] devices = env.getScreenDevices();

            for (int i = 0; i < devices.length && transparencyCapableGC == null; i++) {
                GraphicsConfiguration[] configs = devices[i].getConfigurations();
                for (int j = 0; j < configs.length && transparencyCapableGC == null; j++) {
                    if (AWTUtilities.isTranslucencyCapable(configs[j])) {
                        transparencyCapableGC = configs[j];
                    }
                }
            }
        }
        return transparencyCapableGC;
    }
}