Limit monitor-specific scaling to supported autoscale modes

These changes have following affects:

- Upon starting eclipse product when monitor-specific scaling is set
with unsupported autoscale mode, it will show a error dialog and
application won't start.
- User won't be able to enable monitor-specific scaling from appearance
page if unsupported autoscale mode is set from property or ini file.
- User can then either force the unsupported autoscale mode with monitor
specific-scaling by setting swt.autoScale.force to true or switch to
supported autoscale mode.

Author: ShahzaibIbrahim

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/Workbench.java

@@ -704,6 +704,13 @@ private static void setRescaleAtRuntimePropertyFromPreference() {
 					.getBoolean(IWorkbenchPreferenceConstants.RESCALING_AT_RUNTIME, true);
 			System.setProperty(SWT_RESCALE_AT_RUNTIME_PROPERTY, Boolean.toString(rescaleAtRuntime));
 		}
+
+		if (DPIUtil.isMonitorSpecificScalingActive() && !DPIUtil.isSetupCompatibleToMonitorSpecificScaling()) {
+			System.setProperty(SWT_RESCALE_AT_RUNTIME_PROPERTY, Boolean.toString(false));
+			MessageDialog.openError(new Shell(Display.getDefault()),
+					WorkbenchMessages.RescaleAtRuntimeIncompatibilityTitle,
+					NLS.bind(WorkbenchMessages.RescaleAtRuntimeIncompatibilityDescription));
+		}
 	}
 
 	private static void setSearchContribution(MApplication app, boolean enabled) {

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/WorkbenchMessages.java

@@ -36,6 +36,12 @@ public class WorkbenchMessages extends NLS {
 
 	public static String RescaleAtRuntimeDescription;
 
+	public static String RescaleAtRuntimeDisabledDescription;
+
+	public static String RescaleAtRuntimeIncompatibilityTitle;
+
+	public static String RescaleAtRuntimeIncompatibilityDescription;
+
 	public static String RescaleAtRuntimeEnabled;
 
 	public static String RescaleAtRuntimeSettingChangeWarningTitle;

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/dialogs/ViewsPreferencePage.java

@@ -53,6 +53,7 @@
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.fieldassist.ControlDecoration;
 import org.eclipse.jface.fieldassist.FieldDecorationRegistry;
+import org.eclipse.jface.layout.GridDataFactory;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.preference.PreferencePage;
 import org.eclipse.jface.viewers.ArrayContentProvider;
@@ -65,7 +66,9 @@
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
+import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.internal.DPIUtil;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
@@ -222,7 +225,16 @@ private void createRescaleAtRuntimeCheckButton(Composite parent) {
 				.getBoolean(IWorkbenchPreferenceConstants.RESCALING_AT_RUNTIME, true);
 		rescaleAtRuntime = createCheckButton(parent, WorkbenchMessages.RescaleAtRuntimeEnabled,
 				initialStateRescaleAtRuntime);
-		rescaleAtRuntime.setToolTipText(WorkbenchMessages.RescaleAtRuntimeDescription);
+		if (!DPIUtil.isSetupCompatibleToMonitorSpecificScaling()) {
+			rescaleAtRuntime.setEnabled(false);
+			Font font = parent.getFont();
+			Composite note = createNoteComposite(font, parent, WorkbenchMessages.Preference_note,
+					WorkbenchMessages.RescaleAtRuntimeDisabledDescription);
+			note.setLayoutData(GridDataFactory.swtDefaults().span(2, 1).create());
+		} else {
+			rescaleAtRuntime.setEnabled(true);
+			rescaleAtRuntime.setToolTipText(WorkbenchMessages.RescaleAtRuntimeDescription);
+		}
 	}
 
 	private void createThemeIndependentComposits(Composite comp) {

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/messages.properties

@@ -503,7 +503,10 @@ ThemeChangeWarningTitle = Theme Changed
 RescaleAtRuntimeSettingChangeWarningTitle = DPI Setting Changed
 RescaleAtRuntimeSettingChangeWarningText = Restart for the DPI setting changes to take effect
 RescaleAtRuntimeDescription = Activating this option will dynamically scale all windows according to the monitor they are currently in
+RescaleAtRuntimeDisabledDescription = Incompatible value for system property "swt.autoScale" was defined
 RescaleAtRuntimeEnabled = Use monitor-specific UI &scaling
+RescaleAtRuntimeIncompatibilityTitle = Monitor-Specific Scaling Deactivated
+RescaleAtRuntimeIncompatibilityDescription = Monitor-specific scaling is currently active but an incompatible "swt.autoScale" value is defined. For this reason, monitor-specific scaling has been disabled. Please review your auto-scaling configuration.
 # --- Workbench -----
 WorkbenchPreference_openMode=Open mode
 WorkbenchPreference_doubleClick=D&ouble click