[win32] Utilize temporary image handles

This commit adapts all places, where operation where executed with
OS handles created for a specific zoom that could use any zoom. Therefor
now any existing handle is used or, if none exists yet, a temporary handle
is created and destroyed afterwards.

Author: akoch-yatta

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

@@ -1176,7 +1176,9 @@ Rectangle getBounds(int zoom) {
  */
 @Deprecated
 public Rectangle getBoundsInPixels() {
-	return getBounds(getZoom());
+	return applyUsingAnyHandle(imageHandle -> {
+		return imageHandle.getBounds();
+	});
 }
 
 /**
@@ -1258,7 +1260,9 @@ public ImageData getImageData (int zoom) {
  */
 @Deprecated
 public ImageData getImageDataAtCurrentZoom() {
-	return getImageMetadata(getZoom()).getImageData();
+	return applyUsingAnyHandle(imageHandle -> {
+		return imageHandle.getImageData();
+	});
 }
 
 /**
@@ -1832,6 +1836,19 @@ public String toString () {
 	return "Image {" + zoomLevelToImageHandle + "}";
 }
 
+<T> T applyUsingAnyHandle(Function<ImageHandle, T> function) {
+	if (zoomLevelToImageHandle.isEmpty()) {
+		ImageHandle temporaryHandle = this.imageProvider.newImageHandle(DPIUtil.getDeviceZoom());
+		try {
+			return function.apply(temporaryHandle);
+		} finally {
+			temporaryHandle.destroy();
+		}
+	} else {
+		return function.apply(zoomLevelToImageHandle.values().iterator().next());
+	}
+}
+
 /**
  * Invokes platform specific functionality to allocate a new image.
  * <p>
@@ -2558,6 +2575,10 @@ public ImageHandle(long handle, int zoom) {
 		setImageMetadataForHandle(this, zoom);
 	}
 
+	public Rectangle getBounds() {
+		return new Rectangle(0, 0, width, height);
+	}
+
 	private void setBackground(RGB color) {
 		if (transparentPixel == -1) return;