Guard monitor.zoom with isRescalingAtRuntime flag

This contribution protects the unintended usage of different zoom levels
of different monitors in trasnlating the points and rectangles from
control to display coordinate system when the isRescalingAtRuntime flag
is disabled.

contributes to eclipse-platform#62 and eclipse-platform#127

Author: amartya4256

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

@@ -3157,7 +3157,7 @@ private Rectangle translateRectangleInPixelsInDisplayCoordinateSystem(int x, int
 
 private Rectangle translateRectangleInPixelsInDisplayCoordinateSystem(int x, int y, int width, int height, Monitor monitorOfLocation, Monitor monitorOfArea) {
 	Point topLeft = getPixelsFromPoint(monitorOfLocation, x, y);
-	int zoom = DPIUtil.getZoomForAutoscaleProperty(monitorOfArea.zoom);
+	int zoom = getApplicableMonitorZoom(monitorOfArea);
 	int widthInPixels = DPIUtil.scaleUp(width, zoom);
 	int heightInPixels = DPIUtil.scaleUp(height, zoom);
 	return new Rectangle(topLeft.x, topLeft.y, widthInPixels, heightInPixels);
@@ -3176,12 +3176,16 @@ private Rectangle translateRectangleInPointsInDisplayCoordinateSystem(int x, int
 
 private Rectangle translateRectangleInPointsInDisplayCoordinateSystem(int x, int y, int widthInPixels, int heightInPixels, Monitor monitorOfLocation, Monitor monitorOfArea) {
 	Point topLeft = getPointFromPixels(monitorOfLocation, x, y);
-	int zoom = DPIUtil.getZoomForAutoscaleProperty(monitorOfArea.zoom);
+	int zoom = getApplicableMonitorZoom(monitorOfArea);
 	int width = DPIUtil.scaleDown(widthInPixels, zoom);
 	int height = DPIUtil.scaleDown(heightInPixels, zoom);
 	return new Rectangle(topLeft.x, topLeft.y, width, height);
 }
 
+private int getApplicableMonitorZoom(Monitor monitor) {
+	return DPIUtil.getZoomForAutoscaleProperty(isRescalingAtRuntime() ? monitor.zoom : getDeviceZoom());
+}
+
 long messageProc (long hwnd, long msg, long wParam, long lParam) {
 	switch ((int)msg) {
 		case SWT_RUNASYNC: {
@@ -5480,21 +5484,21 @@ private Monitor getContainingMonitorInPixelsCoordinate(int xInPixels, int yInPix
 }
 
 private Rectangle getMonitorClientAreaInPixels(Monitor monitor) {
-	int zoom = DPIUtil.getZoomForAutoscaleProperty(monitor.zoom);
+	int zoom = getApplicableMonitorZoom(monitor);
 	int widthInPixels = DPIUtil.scaleUp(monitor.clientWidth, zoom);
 	int heightInPixels = DPIUtil.scaleUp(monitor.clientHeight, zoom);
 	return new Rectangle(monitor.clientX, monitor.clientY, widthInPixels, heightInPixels);
 }
 
 private Point getPixelsFromPoint(Monitor monitor, int x, int y) {
-	int zoom = DPIUtil.getZoomForAutoscaleProperty(monitor.zoom);
+	int zoom = getApplicableMonitorZoom(monitor);
 	int mappedX = DPIUtil.scaleUp(x - monitor.clientX, zoom) + monitor.clientX;
 	int mappedY = DPIUtil.scaleUp(y - monitor.clientY, zoom) + monitor.clientY;
 	return new Point(mappedX, mappedY);
 }
 
 private Point getPointFromPixels(Monitor monitor, int x, int y) {
-	int zoom = DPIUtil.getZoomForAutoscaleProperty(monitor.zoom);
+	int zoom = getApplicableMonitorZoom(monitor);
 	int mappedX = DPIUtil.scaleDown(x - monitor.clientX, zoom) + monitor.clientX;
 	int mappedY = DPIUtil.scaleDown(y - monitor.clientY, zoom) + monitor.clientY;
 	return new Point(mappedX, mappedY);