bug6683775.java

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 * version 2 for more details (a copy is included in the LICENSE file that
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/*
 * @test
 * @key headful
 * @bug 6683775 6794764 8186617
 * @summary Painting artifacts is seen when panel is made setOpaque(false) for a
 *          translucent window
 */

import java.awt.Color;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Window;
import java.awt.image.BufferedImage;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class bug6683775 {
    static final int LOC = 100,
            SIZE = 200;

    static JFrame testFrame;
    static JFrame backgroundFrame;
    static BufferedImage capture;

    public static void main(String[] args) throws Exception {
        GraphicsConfiguration gc = getGC();
        if (gc == null || !gc.getDevice().isWindowTranslucencySupported(
                GraphicsDevice.WindowTranslucency.PERPIXEL_TRANSLUCENT)) {
            return;
        }
        Robot robot = new Robot();

        try {
            SwingUtilities.invokeAndWait(() -> {
                testFrame = new JFrame(gc);
                backgroundFrame = new JFrame("Background frame");
                backgroundFrame.setUndecorated(true);
                JPanel panel = new JPanel();
                panel.setBackground(Color.RED);
                backgroundFrame.add(panel);
                backgroundFrame.setBounds(LOC, LOC, SIZE, SIZE);
                backgroundFrame.setVisible(true);

                testFrame.setUndecorated(true);
                JPanel p = new JPanel();
                p.setOpaque(false);
                testFrame.add(p);
                setOpaque(testFrame, false);
                testFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                testFrame.setBounds(LOC, LOC, SIZE, SIZE);
                testFrame.setVisible(true);
            });

            robot.waitForIdle();
            robot.delay(1000);

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

        } finally {
            SwingUtilities.invokeAndWait(testFrame::dispose);
            SwingUtilities.invokeAndWait(backgroundFrame::dispose);
        }

        int redRGB = Color.RED.getRGB();
        if (redRGB != capture.getRGB(SIZE/2, SIZE/2)) {
            throw new RuntimeException("Transparent frame is not transparent!");
        }
    }

    public static void setOpaque(Window window, boolean opaque) {
        Color bg = window.getBackground();
        if (bg == null) {
            bg = new Color(0, 0, 0, 0);
        }
        window.setBackground(new Color(bg.getRed(), bg.getGreen(), bg.getBlue(),
                                       opaque ? 255 : 0));
    }

    private static GraphicsConfiguration getGC() {
        GraphicsConfiguration transparencyCapableGC =
                GraphicsEnvironment.getLocalGraphicsEnvironment()
                        .getDefaultScreenDevice().getDefaultConfiguration();
        if (!transparencyCapableGC.isTranslucencyCapable()) {
            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 (configs[j].isTranslucencyCapable()) {
                        transparencyCapableGC = configs[j];
                    }
                }
            }
        }
        return transparencyCapableGC;
    }
}