Adding loadImageData(zoom) to the AbstractImageProvider Wrapper

This refactoring is required to load unscaled ImageData for all wrappers
The loadImageData for the added functions would have similar logic to
newImageData() except the imageData returned would not be scaled but
would be an ElementAtZoom

Author: arunjose696

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

@@ -1887,6 +1887,12 @@ <T> T applyUsingAnyHandle(Function<ImageHandle, T> function) {
 	return function.apply(zoomLevelToImageHandle.values().iterator().next());
 }
 
+private int getClosestAvailableZoom(int zoom) {
+	TreeSet<Integer> availableZooms = new TreeSet<>(zoomLevelToImageHandle.keySet());
+	int closestZoom = Optional.ofNullable(availableZooms.higher(zoom)).orElse(availableZooms.lower(zoom));
+	return closestZoom;
+}
+
 /**
  * Invokes platform specific functionality to allocate a new image.
  * <p>
@@ -1939,13 +1945,14 @@ public Collection<Integer> getPreservedZoomLevels() {
 		return Collections.emptySet();
 	}
 
+	protected abstract ElementAtZoom<ImageData> loadImageData(int zoom);
+
 	abstract ImageData newImageData(ZoomContext zoomContext);
 
 	abstract AbstractImageProviderWrapper createCopy(Image image);
 
 	ImageData getScaledImageData (int zoom) {
-		TreeSet<Integer> availableZooms = new TreeSet<>(zoomLevelToImageHandle.keySet());
-		int closestZoom = Optional.ofNullable(availableZooms.higher(zoom)).orElse(availableZooms.lower(zoom));
+		int closestZoom = getClosestAvailableZoom(zoom);
 		return DPIUtil.scaleImageData(device, getImageMetadata(new ZoomContext(closestZoom)).getImageData(), zoom, closestZoom);
 	}
 
@@ -2004,12 +2011,18 @@ AbstractImageProviderWrapper createCopy(Image image) {
 	public Collection<Integer> getPreservedZoomLevels() {
 		return Collections.singleton(zoomForHandle);
 	}
+
+	@Override
+	protected ElementAtZoom<ImageData> loadImageData(int zoom) {
+		int closestZoom = getClosestAvailableZoom(zoom);
+		ImageData imageData = getImageMetadata(new ZoomContext(closestZoom)).getImageData();
+		return new ElementAtZoom<>(imageData, closestZoom);
+	}
 }
 
 private abstract class ImageFromImageDataProviderWrapper extends AbstractImageProviderWrapper {
 	private final Map<Integer, ImageData> cachedImageData = new HashMap<>();
 
-	protected abstract ElementAtZoom<ImageData> loadImageData(int zoom);
 
 	void initImage() {
 		// As the init call configured some Image attributes (e.g. type)
@@ -2180,8 +2193,7 @@ protected Rectangle getBounds(int zoom) {
 		return Win32DPIUtils.pointToPixel(rectangle, zoom);
 	}
 
-	@Override
-	ImageData newImageData(ZoomContext zoomContext) {
+	private ImageData resolveBaseOrNewImage(ZoomContext zoomContext) {
 		int targetZoom = zoomContext.targetZoom();
 		if (zoomLevelToImageHandle.isEmpty()) {
 			return createBaseHandle(targetZoom).getImageData();
@@ -2191,7 +2203,24 @@ ImageData newImageData(ZoomContext zoomContext) {
 		if (memGC != null) {
 			return newImageHandle(zoomContext).getImageData();
 		}
-		return getScaledImageData(targetZoom);
+
+		return null;
+	}
+
+	@Override
+	ImageData newImageData(ZoomContext zoomContext) {
+		ImageData data = resolveBaseOrNewImage(zoomContext);
+		return data != null ? data : getScaledImageData(zoomContext.targetZoom);
+	}
+
+	@Override
+	protected ElementAtZoom<ImageData> loadImageData(int zoom) {
+		int closestZoom = getClosestAvailableZoom(zoom);
+		ImageData data = resolveBaseOrNewImage(new ZoomContext(zoom));
+		if (data != null) {
+			return new ElementAtZoom<>(data, zoom);
+		}
+		return new ElementAtZoom<>(getImageMetadata(new ZoomContext(closestZoom)).getImageData(), closestZoom);
 	}
 
 	@Override
@@ -2326,7 +2355,6 @@ private ImageHandle initializeHandleFromSource(int zoom) {
 		return init(imageData, zoom);
 	}
 
-	protected abstract ElementAtZoom<ImageData> loadImageData(int zoom);
 
 	@Override
 	protected Rectangle getBounds(int zoom) {
@@ -2624,6 +2652,11 @@ ImageData newImageData(ZoomContext zoomContext) {
 		return getImageMetadata(zoomContext).getImageData();
 	}
 
+	@Override
+	protected ElementAtZoom<ImageData> loadImageData(int zoom) {
+		return new ElementAtZoom<>(newImageData(new ZoomContext(zoom)), zoom);
+	}
+
 	@Override
 	protected ImageHandle newImageHandle(ZoomContext zoomContext) {
 		currentZoom = zoomContext;