8280991: [XWayland] No displayChanged event after setDisplayMode call

Reviewed-by: honkar, prr

Author: Alexander Zvegintsev

src/java.desktop/unix/classes/sun/awt/X11GraphicsDevice.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2025, 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
@@ -72,6 +72,15 @@ public final class X11GraphicsDevice extends GraphicsDevice
     private boolean shutdownHookRegistered;
     private int scale;
 
+    // Wayland clients are by design not allowed to change the resolution in Wayland.
+    // XRandR in Xwayland is just an emulation, it doesn't actually change the resolution.
+    // This emulation is per window/x11 client, so different clients can have
+    // different emulated resolutions at the same time.
+    // So any request to get the current display mode will always return
+    // the original screen resolution, even if we are in emulated resolution.
+    // To handle this situation, we store the last set display mode in this variable.
+    private volatile DisplayMode xwlCurrentDisplayMode;
+
     public X11GraphicsDevice(int screennum) {
         this.screen = screennum;
         this.scale = initScaleFactor();
@@ -117,6 +126,20 @@ public int scaleDown(int x) {
 
     private Rectangle getBoundsImpl() {
         Rectangle rect = pGetBounds(getScreen());
+
+        if (XToolkit.isOnWayland() && xwlCurrentDisplayMode != null) {
+            // XRandR resolution change in Xwayland is an emulation,
+            // and implemented in such a way that multiple display modes
+            // for a device are only available in a single screen scenario,
+            // if we have multiple screens they will each have a single display mode
+            // (no emulated resolution change is available).
+            // So we don't have to worry about x and y for a screen here.
+            rect.setSize(
+                    xwlCurrentDisplayMode.getWidth(),
+                    xwlCurrentDisplayMode.getHeight()
+            );
+        }
+
         if (getScaleFactor() != 1) {
             rect.x = scaleDown(rect.x);
             rect.y = scaleDown(rect.y);
@@ -400,10 +423,19 @@ private DisplayMode getDefaultDisplayMode() {
     @Override
     public synchronized DisplayMode getDisplayMode() {
         if (isFullScreenSupported()) {
+            if (XToolkit.isOnWayland() && xwlCurrentDisplayMode != null) {
+                return xwlCurrentDisplayMode;
+            }
+
             DisplayMode mode = getCurrentDisplayMode(screen);
             if (mode == null) {
                 mode = getDefaultDisplayMode();
             }
+
+            if (XToolkit.isOnWayland()) {
+                xwlCurrentDisplayMode = mode;
+            }
+
             return mode;
         } else {
             if (origDisplayMode == null) {
@@ -474,6 +506,10 @@ public synchronized void setDisplayMode(DisplayMode dm) {
                           dm.getWidth(), dm.getHeight(),
                           dm.getRefreshRate());
 
+        if (XToolkit.isOnWayland()) {
+            xwlCurrentDisplayMode = dm;
+        }
+
         // update bounds of the fullscreen window
         w.setBounds(0, 0, dm.getWidth(), dm.getHeight());
 

test/jdk/ProblemList.txt

@@ -499,7 +499,6 @@ java/awt/image/multiresolution/MultiResolutionJOptionPaneIconTest.java 8274106 m
 
 # Wayland related
 
-java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java 8280991 linux-x64
 java/awt/FullScreen/SetFullScreenTest.java 8332155 linux-x64
 
 ############################################################################

test/jdk/java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2025, 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
@@ -52,6 +52,10 @@ public void paint(Graphics g) {
                 super.paint(g);
                 g.setColor(Color.GREEN);
                 g.fillRect(0, 0, getWidth(), getHeight());
+                g.setColor(Color.RED);
+                DisplayMode displayMode =
+                        getGraphicsConfiguration().getDevice().getDisplayMode();
+                g.drawString(displayMode.toString(), 100, 100);
             }
         };
         try {

test/jdk/java/awt/FullScreen/NoResizeEventOnDMChangeTest/NoResizeEventOnDMChangeTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2025, 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
@@ -26,6 +26,8 @@
  * @bug 6646411
  * @summary Tests that full screen window and its children receive resize
             event when display mode changes
+ * @library /test/lib
+ * @build   jdk.test.lib.Platform jtreg.SkippedException
  * @run main/othervm NoResizeEventOnDMChangeTest
  * @run main/othervm -Dsun.java2d.d3d=false NoResizeEventOnDMChangeTest
  */
@@ -44,9 +46,21 @@
 import java.awt.event.ComponentEvent;
 import java.awt.event.WindowAdapter;
 import java.awt.event.WindowEvent;
+import java.io.BufferedReader;
+import java.io.IOException;
+
+import static java.util.concurrent.TimeUnit.SECONDS;
+import jdk.test.lib.Platform;
+import jtreg.SkippedException;
 
 public class NoResizeEventOnDMChangeTest {
+
     public static void main(String[] args) {
+        if (Platform.isOnWayland() && !isFixDelivered()) {
+            throw new SkippedException("Test skipped because fix was not" +
+                    "delivered in current GnomeShell version");
+        }
+
         final GraphicsDevice gd = GraphicsEnvironment.
             getLocalGraphicsEnvironment().getDefaultScreenDevice();
 
@@ -231,4 +245,34 @@ public synchronized int getDmChanges() {
             return dmChanges;
         }
     }
+
+    private static boolean isFixDelivered() {
+        try {
+            Process process =
+                    new ProcessBuilder("/usr/bin/gnome-shell", "--version")
+                            .start();
+
+            try (BufferedReader reader = process.inputReader()) {
+                if (process.waitFor(2, SECONDS) &&  process.exitValue() == 0) {
+                    String line = reader.readLine();
+                    if (line != null) {
+                        System.out.println("Gnome shell version: " + line);
+                        String[] versionComponents = line
+                                .replaceAll("[^\\d.]", "")
+                                .split("\\.");
+
+                        if (versionComponents.length >= 1) {
+                            return Integer.parseInt(versionComponents[0]) > 42;
+                        }
+                    }
+                }
+            }
+        } catch (IOException
+                 | InterruptedException
+                 | IllegalThreadStateException
+                 | NumberFormatException ignored) {
+        }
+
+        return false;
+    }
 }