Moving methods from Win32DPIUtil to DPIUtil for autoscaling

Workbench needs few methods from DPIUtil that were only present for
Win32. Keeping the functionality for Win32DPIUtil as is, just making
them available for DPIUtil.

Author: ShahzaibIbrahim

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

@@ -25,7 +25,7 @@ protected ResetMonitorSpecificScalingExtension() {
 
 	@Override
 	public void beforeEach(ExtensionContext context) throws Exception {
-		wasMonitorSpecificScalingActive = Win32DPIUtils.isMonitorSpecificScalingActive();
+		wasMonitorSpecificScalingActive = DPIUtil.isMonitorSpecificScalingActive();
 		Display.getDefault().dispose();
 	}
 

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

@@ -51,6 +51,19 @@ public static Optional<AutoScaleMethod> forString(String s) {
 
 	private static String autoScaleValue;
 
+	private static final Set<String> ALLOWED_AUTOSCALE_VALUES_FOR_UPDATE_ON_RUNTIME = Set.of("quarter", "exact", "false");
+	/**
+	 * System property to enable to scale the application on runtime
+	 * when a DPI change is detected.
+	 * <ul>
+	 * <li>"true": the application is scaled on DPI changes</li>
+	 * <li>"false": the application will remain in its initial scaling</li>
+	 * </ul>
+	 * <b>Important:</b> This flag is only parsed and used on Win32. Setting it to
+	 * true on GTK or cocoa will be ignored.
+	 */
+	static final String SWT_AUTOSCALE_UPDATE_ON_RUNTIME = "swt.autoScale.updateOnRuntime";
+
 	/**
 	 * System property that controls the autoScale functionality.
 	 * <ul>
@@ -89,20 +102,53 @@ public static Optional<AutoScaleMethod> forString(String s) {
 
 	static {
 		autoScaleValue = System.getProperty (SWT_AUTOSCALE);
-
+		setUseSmoothScalingByDefaultProvider(() -> isMonitorSpecificScalingActive());
 		String value = System.getProperty (SWT_AUTOSCALE_METHOD);
 		AUTO_SCALE_METHOD_SETTING = AutoScaleMethod.forString(value).orElse(AutoScaleMethod.AUTO);
 		autoScaleMethod = AUTO_SCALE_METHOD_SETTING != AutoScaleMethod.AUTO ? AUTO_SCALE_METHOD_SETTING : AutoScaleMethod.NEAREST;
 	}
 
-static String getAutoScaleValue() {
+public static String getAutoScaleValue() {
 	return autoScaleValue;
 }
 
 static void setAutoScaleValue(String autoScaleValueArg) {
 	autoScaleValue = autoScaleValueArg;
 }
 
+/**
+ * Returns {@code true} only if the current setup is compatible
+ * with monitor-specific scaling. Returns {@code false} if:
+ * <ul>
+ *   <li>Not running on Windows</li>
+ *   <li>The current auto-scale mode is incompatible</li>
+ * </ul>
+ *
+ * <p>Allowed values: {@code quarter}, {@code exact}.
+ *
+ */
+public static boolean isSetupCompatibleToMonitorSpecificScaling() {
+	if (DPIUtil.getAutoScaleValue() == null) {
+		return false;
+	}
+
+	if(ALLOWED_AUTOSCALE_VALUES_FOR_UPDATE_ON_RUNTIME.contains(DPIUtil.getAutoScaleValue().toLowerCase())) {
+		return true;
+	}
+	try {
+		Integer.parseInt(DPIUtil.getAutoScaleValue());
+		return true;
+	} catch (NumberFormatException e) {
+		// unsupported value, use default
+	}
+	return false;
+}
+
+public static boolean isMonitorSpecificScalingActive() {
+	boolean updateOnRuntimeValue = Boolean.getBoolean (DPIUtil.SWT_AUTOSCALE_UPDATE_ON_RUNTIME);
+	return updateOnRuntimeValue;
+}
+
 public static int pixelToPoint(int size, int zoom) {
 	if (zoom == 100 || size == SWT.DEFAULT) return size;
 	float scaleFactor = getScalingFactor (zoom);

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/Win32DPIUtils.java

@@ -33,21 +33,6 @@
  * @noreference This class is not intended to be referenced by clients
  */
 public class Win32DPIUtils {
-	/**
-	 * System property to enable to scale the application on runtime
-	 * when a DPI change is detected.
-	 * <ul>
-	 * <li>"true": the application is scaled on DPI changes</li>
-	 * <li>"false": the application will remain in its initial scaling</li>
-	 * </ul>
-	 * <b>Important:</b> This flag is only parsed and used on Win32. Setting it to
-	 * true on GTK or cocoa will be ignored.
-	 */
-	private static final String SWT_AUTOSCALE_UPDATE_ON_RUNTIME = "swt.autoScale.updateOnRuntime";
-
-	static {
-	    DPIUtil.setUseSmoothScalingByDefaultProvider(() -> isMonitorSpecificScalingActive());
-	}
 
 	public static boolean setDPIAwareness(int desiredDpiAwareness) {
 		if (desiredDpiAwareness == OS.GetThreadDpiAwarenessContext()) {
@@ -278,55 +263,20 @@ public static Rectangle pointToPixel(Drawable drawable, Rectangle rect, int zoom
 	}
 
 	public static void setMonitorSpecificScaling(boolean activate) {
-		System.setProperty(SWT_AUTOSCALE_UPDATE_ON_RUNTIME, Boolean.toString(activate));
+		System.setProperty(DPIUtil.SWT_AUTOSCALE_UPDATE_ON_RUNTIME, Boolean.toString(activate));
 	}
 
 	public static void setAutoScaleForMonitorSpecificScaling() {
 		boolean isDefaultAutoScale = DPIUtil.getAutoScaleValue() == null;
 		if (isDefaultAutoScale) {
 			DPIUtil.setAutoScaleValue("quarter");
-		} else if (!isSupportedAutoScaleForMonitorSpecificScaling()) {
+		} else if (!DPIUtil.isSetupCompatibleToMonitorSpecificScaling()) {
 			throw new SWTError(SWT.ERROR_NOT_IMPLEMENTED,
 					"monitor-specific scaling is only implemented for auto-scale values \"quarter\", \"exact\", \"false\" or a concrete zoom value, but \""
 							+ DPIUtil.getAutoScaleValue() + "\" has been specified");
 		}
 	}
 
-	/**
-	 * Monitor-specific scaling on Windows only supports auto-scale modes in which
-	 * all elements (font, images, control bounds etc.) are scaled equally or almost
-	 * equally. The previously default mode "integer"/"integer200", which rounded
-	 * the scale factor for everything but fonts to multiples of 100, is complex and
-	 * difficult to realize with monitor-specific rescaling of UI elements. Since a
-	 * uniform scale factor for everything should perspectively be used anyway,
-	 * there will be support for complex auto-scale modes for monitor-specific
-	 * scaling.
-	 *
-	 * The supported modes are "quarter" and "exact" or explicit zoom values given
-	 * by the value itself or "false". Every other value will be treated as
-	 * "integer"/"integer200" and is thus not supported.
-	 */
-	private static boolean isSupportedAutoScaleForMonitorSpecificScaling() {
-		if (DPIUtil.getAutoScaleValue() == null) {
-			return false;
-		}
-		switch (DPIUtil.getAutoScaleValue().toLowerCase()) {
-			case "false", "quarter", "exact": return true;
-		}
-		try {
-			Integer.parseInt(DPIUtil.getAutoScaleValue());
-			return true;
-		} catch (NumberFormatException e) {
-			// unsupported value, use default
-		}
-		return false;
-	}
-
-	public static boolean isMonitorSpecificScalingActive() {
-		boolean updateOnRuntimeValue = Boolean.getBoolean (SWT_AUTOSCALE_UPDATE_ON_RUNTIME);
-		return updateOnRuntimeValue;
-	}
-
 	public static int getPrimaryMonitorZoomAtStartup() {
 		long hDC = OS.GetDC(0);
 		int dpi = OS.GetDeviceCaps(hDC, OS.LOGPIXELSX);

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

@@ -949,7 +949,7 @@ public void close () {
 protected void create (DeviceData data) {
 	checkSubclass ();
 	checkDisplay (thread = Thread.currentThread (), true);
-	if (Win32DPIUtils.isMonitorSpecificScalingActive()) {
+	if (DPIUtil.isMonitorSpecificScalingActive()) {
 		setMonitorSpecificScaling(true);
 		Win32DPIUtils.setAutoScaleForMonitorSpecificScaling();
 	}