[GTK] Simplify logic for refreshing images on zoom change

The implementation for refreshing images on zoom change repeatedly
checks the same conditions and sets the same values. This change
replaces these repetitions with an early return and a unified
post-processing.

Author: HeikoKlare

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

@@ -726,51 +726,33 @@ public Image(Device device, ImageGcDrawer imageGcDrawer, int width, int height)
  *
  * @noreference This function is not intended to be referenced by clients.
  */
-public boolean internal_gtk_refreshImageForZoom() {
-	return refreshImageForZoom();
+public void internal_gtk_refreshImageForZoom() {
+	refreshImageForZoom();
 }
 
 /**
  * Refresh the Image based on the zoom level, if required.
- *
- * @return true if image is refreshed
  */
-boolean refreshImageForZoom () {
-	boolean refreshed = false;
+void refreshImageForZoom () {
 	int deviceZoom = DPIUtil.getDeviceZoom();
+	if (deviceZoom == currentDeviceZoom) {
+		return;
+	}
 	if (imageFileNameProvider != null) {
-		int deviceZoomLevel = deviceZoom;
-		if (deviceZoomLevel != currentDeviceZoom) {
-			/* Release current native resources */
-			destroy ();
-			initFromFileNameProvider(deviceZoomLevel);
-			init ();
-			refreshed = true;
-			currentDeviceZoom = deviceZoomLevel;
-		}
+		reinitializeImage(deviceZoom, zoom -> initFromFileNameProvider(zoom));
 	} else if (imageDataProvider != null) {
-		int deviceZoomLevel = deviceZoom;
-		if (deviceZoomLevel != currentDeviceZoom) {
-			/* Release current native resources */
-			destroy ();
-			initFromImageDataProvider(deviceZoomLevel);
-			init();
-			refreshed = true;
-			currentDeviceZoom = deviceZoomLevel;
-		}
+		reinitializeImage(deviceZoom, zoom -> initFromImageDataProvider(zoom));
 	} else if (imageGcDrawer != null) {
-		int deviceZoomLevel = deviceZoom;
-		if (deviceZoomLevel != currentDeviceZoom) {
-			ImageData data = drawWithImageGcDrawer(width, height, deviceZoomLevel);
-			/* Release current native resources */
-			destroy ();
-			init(data);
-			init();
-			refreshed = true;
-			currentDeviceZoom = deviceZoomLevel;
-		}
+		reinitializeImage(deviceZoom, zoom -> init(drawWithImageGcDrawer(width, height, zoom)));
 	}
-	return refreshed;
+}
+
+private void reinitializeImage(int zoom, IntConsumer initializerForZoom) {
+	/* Release current native resources */
+	destroy ();
+	initializerForZoom.accept(zoom);
+	init();
+	currentDeviceZoom = zoom;
 }
 
 void initNative(String filename) {