Assign Windows runtime rescaling to Display instead of DPIUtil

bundles/org.eclipse.swt/Eclipse SWT Tests/win32/org/eclipse/swt/internal/Win32AutoscaleTestBase.java

@@ -20,7 +20,6 @@
 public abstract class Win32AutoscaleTestBase {
 	protected Display display;
 	protected Shell shell;
-	private boolean autoScaleOnRuntime;
 
 	@BeforeAll
 	public static void assumeIsFittingPlatform() {
@@ -29,9 +28,8 @@ public static void assumeIsFittingPlatform() {
 
 	@BeforeEach
 	public void setUpTest() {
-		autoScaleOnRuntime = DPITestUtil.isAutoScaleOnRuntimeActive();
 		display = Display.getDefault();
-		autoScaleOnRuntime(true);
+		display.setRescalingAtRuntime(true);
 		shell = new Shell(display);
 	}
 
@@ -40,13 +38,7 @@ public void tearDownTest() {
 		if (shell != null) {
 			shell.dispose();
 		}
-		autoScaleOnRuntime(autoScaleOnRuntime);
-	}
-
-	protected void autoScaleOnRuntime (boolean autoScaleOnRuntime) {
-		DPITestUtil.setAutoScaleOnRunTime(autoScaleOnRuntime);
-		// dispose a existing font registry for the default display
-		SWTFontProvider.disposeFontRegistry(display);
+		display.dispose();
 	}
 
 	protected void changeDPIZoom (int nativeZoom) {

bundles/org.eclipse.swt/Eclipse SWT Tests/win32/org/eclipse/swt/widgets/ControlWin32Tests.java

@@ -30,7 +30,7 @@ class ControlWin32Tests extends Win32AutoscaleTestBase {
 
 	@Test
 	public void testScaleFontCorrectlyInAutoScaleSzenario() {
-		assertTrue("Autoscale property is not set to true", DPITestUtil.isAutoScaleOnRuntimeActive());
+		assertTrue("Autoscale property is not set to true", display.isRescalingAtRuntime());
 
 		int scalingFactor = 2;
 		Control control = new Composite(shell, SWT.NONE);
@@ -54,8 +54,8 @@ public void testScaleFontCorrectlyInAutoScaleSzenario() {
 
 	@Test
 	public void testDoNotScaleFontCorrectlyInNoAutoScaleSzenario() {
-		autoScaleOnRuntime(false);
-		assertFalse("Autoscale property is not set to false", DPITestUtil.isAutoScaleOnRuntimeActive());
+		display.setRescalingAtRuntime(false);
+		assertFalse("Autoscale property is not set to false", display.isRescalingAtRuntime());
 
 		int scalingFactor = 2;
 		Control control = new Composite(shell, SWT.NONE);

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java

@@ -6832,4 +6832,33 @@ static long windowProc(long id, long sel, long arg0, long arg1, long arg2, long
 static boolean isActivateShellOnForceFocus() {
 	return "true".equals(System.getProperty("org.eclipse.swt.internal.activateShellOnForceFocus", "true")); //$NON-NLS-1$
 }
+
+/**
+ * {@return whether rescaling of shells at runtime when the DPI scaling of a
+ * shell's monitor changes is activated for this device}
+ * <p>
+ * <b>Note:</b> This functionality is only available on Windows. Calling this
+ * method on other operating system will always return false.
+ *
+ * @since 3.127
+ */
+public boolean isRescalingAtRuntime() {
+	return false;
+}
+
+/**
+ * Activates or deactivates rescaling of shells at runtime whenever the DPI
+ * scaling of the shell's monitor changes. This is only safe to call as long as
+ * no shell has been created for this display. When changing the value after a
+ * shell has been created for this display, the effect is undefined.
+ * <p>
+ * <b>Note:</b> This functionality is only available on Windows. Calling this
+ * method on other operating system will have no effect.
+ *
+ * @param activate whether rescaling shall be activated or deactivated
+ * @since 3.127
+ */
+public void setRescalingAtRuntime(boolean activate) {
+	// not implemented for Cocoa
+}
 }

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java

@@ -110,10 +110,8 @@ private static enum AutoScaleMethod { AUTO, NEAREST, SMOOTH }
 			}
 		}
 
-		if ("win32".equals(SWT.getPlatform())) {
-			String updateOnRuntimeValue = System.getProperty (SWT_AUTOSCALE_UPDATE_ON_RUNTIME);
-			autoScaleOnRuntime = Boolean.parseBoolean(updateOnRuntimeValue);
-		}
+		String updateOnRuntimeValue = System.getProperty (SWT_AUTOSCALE_UPDATE_ON_RUNTIME);
+		autoScaleOnRuntime = Boolean.parseBoolean(updateOnRuntimeValue);
 	}
 
 /**
@@ -669,10 +667,6 @@ public static boolean isAutoScaleOnRuntimeActive() {
 	return autoScaleOnRuntime;
 }
 
-static boolean setAutoScaleOnRuntimeActive(boolean value) {
-	return autoScaleOnRuntime = value;
-}
-
 /**
  * AutoScale ImageDataProvider.
  */

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java

@@ -6266,4 +6266,34 @@ static int _getDeviceZoom (long monitor_num) {
 static boolean isActivateShellOnForceFocus() {
 	return "true".equals(System.getProperty("org.eclipse.swt.internal.activateShellOnForceFocus", "true")); //$NON-NLS-1$
 }
+
+/**
+ * {@return whether rescaling of shells at runtime when the DPI scaling of a
+ * shell's monitor changes is activated for this device}
+ * <p>
+ * <b>Note:</b> This functionality is only available on Windows. Calling this
+ * method on other operating system will always return false.
+ *
+ * @since 3.127
+ */
+public boolean isRescalingAtRuntime() {
+	return false;
+}
+
+/**
+ * Activates or deactivates rescaling of shells at runtime whenever the DPI
+ * scaling of the shell's monitor changes. This is only safe to call as long as
+ * no shell has been created for this display. When changing the value after a
+ * shell has been created for this display, the effect is undefined.
+ * <p>
+ * <b>Note:</b> This functionality is only available on Windows. Calling this
+ * method on other operating system will have no effect.
+ *
+ * @param activate whether rescaling shall be activated or deactivated
+ * @since 3.127
+ */
+public void setRescalingAtRuntime(boolean activate) {
+	// not implemented for GTK
+}
+
 }

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/SWTFontProvider.java

@@ -16,6 +16,7 @@
 import java.util.*;
 
 import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.widgets.*;
 
 /**
  * This internal class is used to provide and cache fonts scaled for different zoom levels in the win32
@@ -47,7 +48,7 @@ public static void disposeFontRegistry(Device device) {
 	}
 
 	private static SWTFontRegistry newFontRegistry(Device device) {
-		if (DPIUtil.isAutoScaleOnRuntimeActive()) {
+		if (device instanceof Display display && display.isRescalingAtRuntime()) {
 			return new ScalingSWTFontRegistry(device);
 		}
 		return new DefaultSWTFontRegistry(device);

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java

@@ -4910,13 +4910,13 @@ LRESULT WM_DPICHANGED (long wParam, long lParam) {
 		event.detail = newNativeZoom;
 		event.doit = true;
 
-		if (DPIUtil.isAutoScaleOnRuntimeActive()) {
+		if (getDisplay().isRescalingAtRuntime()) {
 			DPIUtil.setDeviceZoom (newNativeZoom);
 		}
 
 		notifyListeners(SWT.ZoomChanged, event);
 
-		if (DPIUtil.isAutoScaleOnRuntimeActive()) {
+		if (getDisplay().isRescalingAtRuntime()) {
 			RECT rect = new RECT ();
 			COM.MoveMemory(rect, lParam, RECT.sizeof);
 			this.setBoundsInPixels(rect.left, rect.top, rect.right - rect.left, rect.bottom-rect.top);

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java

@@ -138,6 +138,7 @@ public class Display extends Device implements Executor {
 	EventTable eventTable, filterTable;
 	boolean useOwnDC;
 	boolean externalEventLoop; // events are dispatched outside SWT, e.g. TrackPopupMenu or DoDragDrop
+	private boolean rescalingAtRuntime;
 
 	/* Widget Table */
 	private Map<Long, Control> controlByHandle;
@@ -582,28 +583,8 @@ public Display () {
  */
 public Display (DeviceData data) {
 	super (data);
-	initializeProperDPIAwareness();
-}
-
-private void initializeProperDPIAwareness() {
-	if (!DPIUtil.isAutoScaleOnRuntimeActive()) {
-		return;
-	}
-	// Auto scaling on runtime requires DPI awareness mode "Per Monitor V2"
-	boolean perMonitorV2Available = OS.WIN32_BUILD > OS.WIN32_BUILD_WIN10_1809;
-	if (!perMonitorV2Available) {
-		System.err.println(
-				"***WARNING: rescaling at runtime is activated but the OS version does not support required DPI awareness mode PerMonitorV2.");
-		return;
-	}
-
-	boolean alreadyUsesPerMonitorV2 = OS.GetThreadDpiAwarenessContext() == OS.DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2;
-	if (alreadyUsesPerMonitorV2) {
-		return;
-	}
-	long setDpiAwarenessResult = OS.SetThreadDpiAwarenessContext(OS.DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
-	if (setDpiAwarenessResult == 0L) {
-		System.err.println("***WARNING: setting DPI awareness to PerMonitorV2 failed.");
+	if (DPIUtil.isAutoScaleOnRuntimeActive()) {
+		setRescalingAtRuntime(true);
 	}
 }
 
@@ -5267,4 +5248,62 @@ static String withCrLf (String string) {
 static boolean isActivateShellOnForceFocus() {
 	return "true".equals(System.getProperty("org.eclipse.swt.internal.activateShellOnForceFocus", "true")); //$NON-NLS-1$
 }
+
+/**
+ * {@return whether rescaling of shells at runtime when the DPI scaling of a
+ * shell's monitor changes is activated for this device}
+ * <p>
+ * <b>Note:</b> This functionality is only available on Windows. Calling this
+ * method on other operating system will always return false.
+ *
+ * @since 3.127
+ */
+public boolean isRescalingAtRuntime() {
+	return rescalingAtRuntime;
+}
+
+/**
+ * Activates or deactivates rescaling of shells at runtime whenever the DPI
+ * scaling of the shell's monitor changes. This is only safe to call as long as
+ * no shell has been created for this display. When changing the value after a
+ * shell has been created for this display, the effect is undefined.
+ * <p>
+ * <b>Note:</b> This functionality is only available on Windows. Calling this
+ * method on other operating system will have no effect.
+ *
+ * @param activate whether rescaling shall be activated or deactivated
+ * @since 3.127
+ */
+public void setRescalingAtRuntime(boolean activate) {
+	rescalingAtRuntime = activate;
+	// dispose a existing font registry for the default display
+	SWTFontProvider.disposeFontRegistry(this);
+	setProperDPIAwareness();
+}
+
+private void setProperDPIAwareness() {
+	long desiredDpiAwareness = OS.DPI_AWARENESS_CONTEXT_SYSTEM_AWARE;
+	if (OS.WIN32_BUILD < OS.WIN32_BUILD_WIN10_1607) {
+		System.err.println("***WARNING: the OS version does not support setting DPI awareness.");
+		return;
+	}
+	if (rescalingAtRuntime) {
+		desiredDpiAwareness = OS.DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2;
+		// Auto scaling on runtime requires DPI awareness mode "Per Monitor V2"
+		boolean perMonitorV2Available = OS.WIN32_BUILD >= OS.WIN32_BUILD_WIN10_1809;
+		if (!perMonitorV2Available) {
+			System.err.println(
+					"***WARNING: rescaling at runtime is activated but the OS version does not support required DPI awareness mode PerMonitorV2.");
+			return;
+		}
+	}
+	if (desiredDpiAwareness == OS.GetThreadDpiAwarenessContext()) {
+		return;
+	}
+	long setDpiAwarenessResult = OS.SetThreadDpiAwarenessContext(desiredDpiAwareness);
+	if (setDpiAwarenessResult == 0L) {
+		System.err.println("***WARNING: setting DPI awareness failed.");
+	}
+}
+
 }

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Shell.java

@@ -313,7 +313,7 @@ public Shell (Display display, int style) {
 	createWidget ();
 
 
-	if (DPIUtil.isAutoScaleOnRuntimeActive()) {
+	if (getDisplay().isRescalingAtRuntime()) {
 		addListener(SWT.ZoomChanged, this::handleZoomEvent);
 	}
 }