8345538: Robot.mouseMove doesn't clamp bounds on macOS when trying to move mouse off screen

Reviewed-by: honkar, prr

Author: Alisen Chung

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 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
@@ -25,6 +25,8 @@
 
 package sun.lwawt.macosx;
 
+import java.awt.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
 import java.awt.Point;
 import java.awt.Rectangle;
 import java.awt.peer.RobotPeer;
@@ -63,7 +65,41 @@ public void mouseMove(int x, int y) {
         mouseLastX = x;
         mouseLastY = y;
 
-        mouseEvent(mouseLastX, mouseLastY, mouseButtonsState, true, true);
+        int leastDiff = Integer.MAX_VALUE;
+        int finX = x;
+        int finY = y;
+
+        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
+        GraphicsDevice[] gs = ge.getScreenDevices();
+        Rectangle[] allScreenBounds = new Rectangle[gs.length];
+
+        for (int i = 0; i < gs.length; i++) {
+            allScreenBounds[i] = gs[i].getDefaultConfiguration().getBounds();
+        }
+
+        for (Rectangle screenBounds : allScreenBounds) {
+            Point cP = calcClosestPoint(x, y, screenBounds);
+
+            int currXDiff = Math.abs(x - cP.x);
+            int currYDiff = Math.abs(y - cP.y);
+            int currDiff = (int) Math.round(Math.hypot(currXDiff, currYDiff));
+
+            if (currDiff == 0) {
+                mouseEvent(mouseLastX, mouseLastY, mouseButtonsState, true, true);
+                return;
+            } if (currDiff < leastDiff) {
+                finX = cP.x;
+                finY = cP.y;
+                leastDiff = currDiff;
+            }
+        }
+
+        mouseEvent(finX, finY, mouseButtonsState, true, true);
+    }
+
+    private Point calcClosestPoint(int x, int y, Rectangle screenBounds) {
+        return new Point(Math.min(Math.max(x, screenBounds.x), screenBounds.x + screenBounds.width - 1),
+                Math.min(Math.max(y, screenBounds.y), screenBounds.y + screenBounds.height - 1));
     }
 
     /**

test/jdk/java/awt/Robot/MouseMoveOffScreen.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 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
+ * 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.GraphicsConfiguration;
+import java.awt.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
+import java.awt.MouseInfo;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.Robot;
+
+/*
+ * @test
+ * @bug 8345538
+ * @summary Tests mouseMove clamping to screen bounds when set to move offscreen
+ * @requires (os.family == "mac")
+ * @key headful
+ * @run main MouseMoveOffScreen
+ */
+
+public class MouseMoveOffScreen {
+    private static final Point STARTING_LOC = new Point(200, 200);
+    private static final Point OFF_SCREEN_LOC = new Point(20000, 200);
+    private static Rectangle[] r;
+
+    public static void main(String[] args) throws Exception {
+        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
+        GraphicsDevice[] gs = ge.getScreenDevices();
+        r = new Rectangle[gs.length];
+
+        for (int i = 0; i < gs.length; i++) {
+            r[i] = gs[i].getDefaultConfiguration().getBounds();
+            System.out.println("Screen: "+ gs[i].getIDstring() + "  Bounds: " + r[i]);
+        }
+
+        Point offsc = validateOffScreen(OFF_SCREEN_LOC);
+        Robot robot = new Robot();
+        robot.mouseMove(STARTING_LOC.x, STARTING_LOC.y);
+        robot.delay(500);
+        robot.mouseMove(offsc.x, offsc.y);
+        robot.delay(500);
+
+        Point currLoc = MouseInfo.getPointerInfo().getLocation();
+
+        if (currLoc == null) {
+            throw new RuntimeException("Test Failed, getLocation returned null.");
+        }
+
+        System.out.println("Current mouse location: " + currLoc);
+        if (currLoc.equals(OFF_SCREEN_LOC)) {
+            throw new RuntimeException("Test Failed, robot moved mouse off screen.");
+        }
+    }
+
+    private static Point validateOffScreen(Point p) {
+        for (Rectangle rect : r) {
+            if (rect.contains(p)) {
+                return validateOffScreen(new Point(p.x * 2, p.y));
+            }
+        }
+        return p;
+    }
+}