[win32] Foward native zoom to draw bitmap in GC

This commit adapts the logic when a bitmap or icon is drawn with the GC
in the windows implementation. As of now,  the autoscale zoom was used to
identify the image handle to use. If the image is itself drawn with a
ImageGCDrawer, information about the original native zoom was lost, which
led to inconsistencies in fonts depending on the auto scale mode. This
commit fowards the native zoom in this case to enable the Image to
initialize the GC accordingly.

fixes #2385

Author: akoch-yatta

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

@@ -1253,7 +1253,7 @@ private void drawImage(Image srcImage, int srcX, int srcY, int srcWidth, int src
 		}
 		return;
 	}
-	long imageHandle = Image.win32_getHandle(srcImage, imageZoom);
+	long imageHandle = srcImage.getHandle(imageZoom, data.nativeZoom);
 	switch (srcImage.type) {
 		case SWT.BITMAP:
 			drawBitmap(srcImage, imageHandle, srcX, srcY, srcWidth, srcHeight, destX, destY, destWidth, destHeight, simple);

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

@@ -835,6 +835,13 @@ public static long win32_getHandle (Image image, int zoom) {
 	return image.getImageMetadata(new ZoomContext(zoom)).handle;
 }
 
+long getHandle (int targetZoom, int nativeZoom) {
+	if (isDisposed()) {
+		return 0L;
+	}
+	return getImageMetadata(new ZoomContext(targetZoom, nativeZoom)).handle;
+}
+
 /**
  * <b>IMPORTANT:</b> This method is not part of the public
  * API for Image. It is marked public only so that it
@@ -2312,7 +2319,7 @@ protected ImageHandle newImageHandle(ZoomContext zoomContext) {
 
 	private ImageHandle initializeHandleFromSource(int zoom) {
 		ElementAtZoom<ImageData> imageDataAtZoom = loadImageData(zoom);
-		ImageData imageData = DPIUtil.scaleImageData (device,imageDataAtZoom.element(), zoom, imageDataAtZoom.zoom());
+		ImageData imageData = DPIUtil.scaleImageData (device, imageDataAtZoom.element(), zoom, imageDataAtZoom.zoom());
 		imageData = adaptImageDataIfDisabledOrGray(imageData);
 		return init(imageData, zoom);
 	}