8006421: GraphicsConfiguration of a frame is changed when the frame is moved to another screen

Reviewed-by: azvegint, serb

src/java.desktop/macosx/classes/sun/lwawt/macosx/CFileDialog.java

@@ -199,6 +199,12 @@ class CFileDialog implements FileDialogPeer {
     public void repositionSecurityWarning() {
     }
 
+    @Override
+    public GraphicsConfiguration getAppropriateGraphicsConfiguration(
+            GraphicsConfiguration gc) {
+        return gc;
+    }
+
     @Override
     public void updateAlwaysOnTopState() {
     }

src/java.desktop/share/classes/java/awt/Window.java

@@ -3221,7 +3221,12 @@ public class Window extends Container implements Accessible {
                     getDefaultScreenDevice().
                     getDefaultConfiguration();
         }
+
         synchronized (getTreeLock()) {
+            WindowPeer peer = (WindowPeer) this.peer;
+            if (peer != null) {
+                gc = peer.getAppropriateGraphicsConfiguration(gc);
+            }
             super.setGraphicsConfiguration(gc);
             if (log.isLoggable(PlatformLogger.Level.FINER)) {
                 log.finer("+ Window.setGraphicsConfiguration(): new GC is \n+ " + getGraphicsConfiguration_NoClientCode() + "\n+ this is " + this);

src/java.desktop/share/classes/java/awt/peer/WindowPeer.java

@@ -118,4 +118,15 @@ public interface WindowPeer extends ContainerPeer {
      * Instructs the peer to update the position of the security warning.
      */
     void repositionSecurityWarning();
+
+    /**
+     * Requests a GC that best suits this Window. The returned GC may differ
+     * from the requested GC passed as the argument to this method. This method
+     * must return a non-null value (given the argument is non-null as well).
+     *
+     * @param gc the requested graphics configuration
+     * @return a graphics configuration that best suits this Window
+     */
+    GraphicsConfiguration getAppropriateGraphicsConfiguration(
+            GraphicsConfiguration gc);
 }

test/jdk/java/awt/Multiscreen/MultiscreenTransparencyTest.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.awt.Color;
+import java.awt.Point;
+import java.awt.Dimension;
+import java.awt.Graphics;
+import java.awt.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseMotionListener;
+import java.lang.reflect.InvocationTargetException;
+
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.SwingUtilities;
+
+/*
+ * @test
+ * @bug 8006421
+ * @key headful
+ * @library /java/awt/regtesthelpers
+ * @build PassFailJFrame
+ * @summary Test to check if Transparency of a frame when dragged is maintained
+ * across multiple screens.
+ * @run main/manual MultiscreenTransparencyTest
+ */
+
+public class MultiscreenTransparencyTest {
+    static Point dragStart = new Point();
+    static JFrame frame;
+    static JPanel panel;
+    static PassFailJFrame passFailJFrame;
+
+    public static void main(String[] args) throws Exception {
+        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
+        GraphicsDevice[] gds = ge.getScreenDevices();
+
+        if (gds.length < 2) {
+            System.out.println("Returning without testing." +
+                    "Min 2 Display screens are required for the test!");
+            return;
+        }
+        SwingUtilities.invokeAndWait(() -> {
+            try {
+                initialize();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            } catch (InvocationTargetException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        passFailJFrame.awaitAndCheck();
+    }
+
+    private static void initialize() throws InterruptedException,
+            InvocationTargetException {
+        final String INSTRUCTIONS = """
+                Instructions to Test:
+                1. This test requires multi screen display setup.
+                2. Drag the red transparent frame with mouse to second monitor.
+                3. If the set transparency is retained then test PASS
+                else test is FAIL.
+                """;
+        panel = new Custom();
+        panel.setOpaque(false);
+        panel.setBackground(null);
+        frame = new JFrame();
+        passFailJFrame = new PassFailJFrame("Test Instructions", INSTRUCTIONS, 5L, 8, 40);
+
+        PassFailJFrame.addTestWindow(frame);
+        PassFailJFrame.positionTestWindow(frame, PassFailJFrame.Position.HORIZONTAL);
+        frame.setUndecorated(true);
+        frame.setBackground(new Color(0, 0, 0, 0));
+        frame.setTitle("Transparency Test");
+        frame.getContentPane().add(panel);
+        frame.setSize(320, 240);
+        frame.setResizable(false);
+        frame.setMinimumSize(new Dimension(1, 1));
+        frame.setLocationRelativeTo(null);
+        frame.setVisible(true);
+
+        frame.addMouseListener(new MouseAdapter() {
+            @Override
+            public void mousePressed(MouseEvent e) {
+                dragStart = e.getPoint();
+            }
+
+            @Override
+            public void mouseReleased(MouseEvent e) {
+                System.err.println(frame.getGraphicsConfiguration());
+            }
+        });
+
+        frame.addMouseMotionListener(new MouseMotionListener() {
+            @Override
+            public void mouseDragged(MouseEvent e) {
+                frame.setLocation(
+                        e.getXOnScreen() - dragStart.x,
+                        e.getYOnScreen() - dragStart.y
+                );
+            }
+
+            @Override
+            public void mouseMoved(MouseEvent e) {
+            }
+        });
+    }
+
+    private static class Custom extends JPanel {
+        @Override
+        protected void paintComponent(Graphics g) {
+            super.paintComponent(g);
+            g.setColor(new Color(255, 0, 0, 127));
+            g.fillOval(0, 0, getWidth(), getHeight());
+        }
+    }
+}