[win32] fix to use zoom dpi for fonts via display

With commit cd8bb13 we adapted the calcuation how to scale up fonts to
fix the calculation for fonts used by the Printer. This introduced an
issue if monitor-specific scaling is active and the primary monitor zoom
is changed, because two different calculation were mixed now. This commit
fixes this inconsistency.

Author: akoch-yatta

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Device.java

@@ -260,9 +260,9 @@ void checkGDIP() {
 protected void create (DeviceData data) {
 }
 
-int computePixels(float height) {
+int computePixels(float height, int zoom) {
 	long hDC = internal_new_GC (null);
-	int pixels = -(int)(0.5f + (height * OS.GetDeviceCaps(hDC, OS.LOGPIXELSY) / 72f));
+	int pixels = -(int)(0.5f + (height / calculateFontConversionFactor(hDC, zoom)));
 	internal_dispose_GC (hDC, null);
 	return pixels;
 }
@@ -271,9 +271,7 @@ float computePoints(LOGFONT logFont, long hFont) {
 	return computePoints(logFont, hFont, SWT.DEFAULT);
 }
 
-float computePoints(LOGFONT logFont, long hFont, int zoom) {
-	long hDC = internal_new_GC (null);
-
+private float calculateFontConversionFactor(long hDC, int zoom) {
 	float conversionFactor = 72f;
 	if (isAutoScalable() && zoom != SWT.DEFAULT) {
 		// For auto scalable devices we need to use a dynamic
@@ -282,6 +280,13 @@ float computePoints(LOGFONT logFont, long hFont, int zoom) {
 	} else {
 		conversionFactor /= OS.GetDeviceCaps(hDC, OS.LOGPIXELSY);
 	}
+	return conversionFactor;
+}
+
+float computePoints(LOGFONT logFont, long hFont, int zoom) {
+	long hDC = internal_new_GC (null);
+
+	float conversionFactor = calculateFontConversionFactor(hDC, zoom);
 	int pixels = 0;
 	if (logFont.lfHeight > 0) {
 		/*

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Font.java

@@ -236,14 +236,7 @@ void init (FontData fd) {
 	if (fd == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 	LOGFONT logFont = fd.data;
 	int lfHeight = logFont.lfHeight;
-	logFont.lfHeight = device.computePixels(fd.height);
-
-	int primaryZoom = extractZoom(device);
-	if (zoom != primaryZoom) {
-		float scaleFactor = 1f * zoom / primaryZoom;
-		logFont.lfHeight *= scaleFactor;
-	}
-
+	logFont.lfHeight = device.computePixels(fd.height, zoom);
 	handle = OS.CreateFontIndirect(logFont);
 	logFont.lfHeight = lfHeight;
 	if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES);