8243925: Toolkit#getScreenInsets() returns wrong value on HiDPI screens (Windows)

src/java.desktop/windows/native/libawt/windows/awt_Toolkit.cpp

@@ -2693,13 +2693,14 @@ Java_sun_awt_windows_WToolkit_getScreenInsets(JNIEnv *env,
         jclass insetsClass = env->FindClass("java/awt/Insets");
         DASSERT(insetsClass != NULL);
         CHECK_NULL_RETURN(insetsClass, NULL);
-
+        Devices::InstanceAccess devices;
+        AwtWin32GraphicsDevice *device = devices->GetDevice(screen);
         insets = env->NewObject(insetsClass,
                 AwtToolkit::insetsMID,
-                rect.top,
-                rect.left,
-                rect.bottom,
-                rect.right);
+                device == NULL ? rect.top : device->ScaleDownY(rect.top),
+                device == NULL ? rect.left : device->ScaleDownX(rect.left),
+                device == NULL ? rect.bottom : device->ScaleDownY(rect.bottom),
+                device == NULL ? rect.right : device->ScaleDownX(rect.right));
     }
 
     if (safe_ExceptionOccurred(env)) {

test/jdk/java/awt/Toolkit/ScreenInsetsDPIVariation/ScreenInsetsDPIVariation.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2020, 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.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
+import java.awt.Insets;
+import java.awt.Toolkit;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import jdk.test.lib.process.OutputAnalyzer;
+import jdk.test.lib.process.ProcessTools;
+
+/**
+ * @test
+ * @bug 8243925
+ * @key headful
+ * @requires (os.family == "windows")
+ * @summary Verifies Toolkit.getScreenInsets using different DPI
+ * @library /test/lib
+ * @run main/othervm -Dsun.java2d.uiScale=1 ScreenInsetsDPIVariation
+ */
+public final class ScreenInsetsDPIVariation {
+
+    public static void main(String[] args) throws Exception {
+        var ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
+        GraphicsDevice[] screenDevices = ge.getScreenDevices();
+        if (args.length == 0) {
+            for (int i = 0; i < screenDevices.length; i++) {
+                var gd = screenDevices[i];
+                var gc = gd.getDefaultConfiguration();
+                Insets insets = Toolkit.getDefaultToolkit().getScreenInsets(gc);
+                checkAllDPI(i, insets);
+            }
+        } else {
+            int screen = Integer.parseInt(args[0]);
+            int left = Integer.parseInt(args[1]);
+            int right = Integer.parseInt(args[2]);
+            int top = Integer.parseInt(args[3]);
+            int bottom = Integer.parseInt(args[4]);
+            double scale = Double.parseDouble(args[5]);
+
+            System.err.println("screen = " + screen);
+            System.err.println("scale = " + scale);
+            if (screen >= screenDevices.length) {
+                return; // devices were changed, skip
+            }
+            var gc = screenDevices[screen].getDefaultConfiguration();
+            Insets insets = Toolkit.getDefaultToolkit().getScreenInsets(gc);
+            check(insets.left, left / scale);
+            check(insets.right, right / scale);
+            check(insets.top, top / scale);
+            check(insets.bottom, bottom / scale);
+        }
+    }
+
+    private static void check(int actual, double expected) {
+        if (actual != clipRound(expected)) {
+            System.err.println("Expected: " + expected);
+            System.err.println("Actual: " + actual);
+            throw new RuntimeException("Wrong size");
+        }
+    }
+
+    private static void checkAllDPI(int screen, Insets insets)
+            throws Exception {
+        for (String dpi : List.of("1", "1.5", "1.75", "2", "2.5", "3", "3.1")) {
+            runProcess(dpi, screen, insets);
+        }
+    }
+
+    public static int clipRound(double coordinate) {
+        double newv = coordinate - 0.5;
+        if (newv < Integer.MIN_VALUE) {
+            return Integer.MIN_VALUE;
+        }
+        if (newv > Integer.MAX_VALUE) {
+            return Integer.MAX_VALUE;
+        }
+        return (int) Math.ceil(newv);
+    }
+
+    private static void runProcess(String dpi, int screen, Insets insets)
+            throws Exception {
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+                "-Dsun.java2d.uiScale=" + dpi,
+                ScreenInsetsDPIVariation.class.getSimpleName(),
+                String.valueOf(screen), String.valueOf(insets.left),
+                String.valueOf(insets.right), String.valueOf(insets.top),
+                String.valueOf(insets.bottom), dpi);
+        Process worker = ProcessTools.startProcess("Worker", pb, null, 20,
+                TimeUnit.SECONDS);
+        new OutputAnalyzer(worker).shouldHaveExitValue(0);
+    }
+}

test/jdk/java/awt/Window/MinimumSizeDPIVariation/MinimumSizeDPIVariation.java

@@ -103,12 +103,12 @@ private static void checkAllDPI(String comp, int w, int h)
             throws Exception {
         if (!Platform.isOSX()) {
             for (String dpi : List.of("1.5", "1.75", "2", "2.5")) {
-                runPocess(dpi, comp, w, h);
+                runProcess(dpi, comp, w, h);
             }
         }
     }
 
-    private static void runPocess(String dpi, String comp, int w, int h)
+    private static void runProcess(String dpi, String comp, int w, int h)
             throws Exception {
         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
                 "-Dsun.java2d.uiScale=" + dpi,