Use the existing image to initialize the GC in ImageGcDrawerWrapper

In ImageGCDrawerWrapper#newImageHandle, we create a new image with existing data to initialize the GC, instead we could use the existing image object and the base handle should be created as it is done in PlainImageDataProvider.

Author: ShahzaibIbrahim

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

@@ -1911,6 +1911,47 @@ protected final ImageHandle newImageHandle(ImageData data, int zoom) {
 			return init(data, zoom);
 		}
 	}
+
+	protected final ImageHandle createBaseHandle(int zoom, int width, int height) {
+		long handle = initBaseHandle(zoom, width, height);
+		ImageHandle imageHandle = new ImageHandle(handle, zoom);
+		zoomLevelToImageHandle.put(zoom, imageHandle);
+		return imageHandle;
+	}
+
+
+	private long initBaseHandle(int zoom, int width, int height) {
+		if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
+		int scaledWidth = DPIUtil.scaleUp (width, zoom);
+		int scaledHeight = DPIUtil.scaleUp (height, zoom);
+		long hDC = device.internal_new_GC(null);
+		long newHandle = OS.CreateCompatibleBitmap(hDC, scaledWidth, scaledHeight);
+		/*
+		* Feature in Windows.  CreateCompatibleBitmap() may fail
+		* for large images.  The fix is to create a DIB section
+		* in that case.
+		*/
+		if (newHandle == 0) {
+			int bits = OS.GetDeviceCaps(hDC, OS.BITSPIXEL);
+			int planes = OS.GetDeviceCaps(hDC, OS.PLANES);
+			int depth = bits * planes;
+			if (depth < 16) depth = 16;
+			if (depth > 24) depth = 24;
+			newHandle = createDIB(scaledWidth, scaledHeight, depth);
+		}
+		if (newHandle != 0) {
+			long memDC = OS.CreateCompatibleDC(hDC);
+			long hOldBitmap = OS.SelectObject(memDC, newHandle);
+			OS.PatBlt(memDC, 0, 0, scaledWidth, scaledHeight, OS.PATCOPY);
+			OS.SelectObject(memDC, hOldBitmap);
+			OS.DeleteDC(memDC);
+		}
+		device.internal_dispose_GC(hDC, null);
+		if (newHandle == 0) {
+			SWT.error(SWT.ERROR_NO_HANDLES, null, device.getLastError());
+		}
+		return newHandle;
+	}
 }
 
 private class ExistingImageHandleProviderWrapper extends AbstractImageProviderWrapper {
@@ -2121,59 +2162,22 @@ protected Rectangle getBounds(int zoom) {
 	@Override
 	ImageData newImageData(int zoom) {
 		if (zoomLevelToImageHandle.isEmpty()) {
-			return createBaseHandle(zoom).getImageData();
+			baseZoom = zoom;
+			return createBaseHandle(zoom, width, height).getImageData();
 		}
 		return getScaledImageData(zoom);
 	}
 
 	@Override
 	protected ImageHandle newImageHandle(int zoom) {
 		if (zoomLevelToImageHandle.isEmpty()) {
-			return createBaseHandle(zoom);
+			baseZoom = zoom;
+			return createBaseHandle(zoom, width, height);
 		}
 		return super.newImageHandle(zoom);
 	}
 
-	private ImageHandle createBaseHandle(int zoom) {
-		long handle = initBaseHandle(zoom);
-		baseZoom = zoom;
-		ImageHandle imageHandle = new ImageHandle(handle, zoom);
-		zoomLevelToImageHandle.put(zoom, imageHandle);
-		return imageHandle;
-	}
 
-	private long initBaseHandle(int zoom) {
-		if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
-		int scaledWidth = DPIUtil.scaleUp (width, zoom);
-		int scaledHeight = DPIUtil.scaleUp (height, zoom);
-		long hDC = device.internal_new_GC(null);
-		long newHandle = OS.CreateCompatibleBitmap(hDC, scaledWidth, scaledHeight);
-		/*
-		* Feature in Windows.  CreateCompatibleBitmap() may fail
-		* for large images.  The fix is to create a DIB section
-		* in that case.
-		*/
-		if (newHandle == 0) {
-			int bits = OS.GetDeviceCaps(hDC, OS.BITSPIXEL);
-			int planes = OS.GetDeviceCaps(hDC, OS.PLANES);
-			int depth = bits * planes;
-			if (depth < 16) depth = 16;
-			if (depth > 24) depth = 24;
-			newHandle = createDIB(scaledWidth, scaledHeight, depth);
-		}
-		if (newHandle != 0) {
-			long memDC = OS.CreateCompatibleDC(hDC);
-			long hOldBitmap = OS.SelectObject(memDC, newHandle);
-			OS.PatBlt(memDC, 0, 0, scaledWidth, scaledHeight, OS.PATCOPY);
-			OS.SelectObject(memDC, hOldBitmap);
-			OS.DeleteDC(memDC);
-		}
-		device.internal_dispose_GC(hDC, null);
-		if (newHandle == 0) {
-			SWT.error(SWT.ERROR_NO_HANDLES, null, device.getLastError());
-		}
-		return newHandle;
-	}
 
 	@Override
 	AbstractImageProviderWrapper createCopy(Image image) {
@@ -2541,28 +2545,25 @@ ImageData newImageData(int zoom) {
 	protected ImageHandle newImageHandle(int zoom) {
 		currentZoom = zoom;
 		int gcStyle = drawer.getGcStyle();
-		Image image;
 		if ((gcStyle & SWT.TRANSPARENT) != 0) {
 			int scaledHeight = DPIUtil.scaleUp(height, zoom);
 			int scaledWidth = DPIUtil.scaleUp(width, zoom);
 			/* Create a 24 bit image data with alpha channel */
 			final ImageData resultData = new ImageData (scaledWidth, scaledHeight, 24, new PaletteData (0xFF, 0xFF00, 0xFF0000));
 			resultData.alphaData = new byte [scaledWidth * scaledHeight];
-			image = new Image(device, resultData, zoom);
+			init(resultData, zoom);
 		} else {
-			image = new Image(device, width, height);
-		}
-		GC gc = new GC(new DrawableWrapper(image, zoom), gcStyle);
+			createBaseHandle(zoom, width, height);
+		};
+		GC gc = new GC(new DrawableWrapper(Image.this, zoom), gcStyle);
 		try {
 			gc.data.nativeZoom = zoom;
 			drawer.drawOn(gc, width, height);
-			ImageData imageData = image.getImageMetadata(zoom).getImageData();
+			ImageData imageData = Image.this.getImageMetadata(zoom).getImageData();
 			drawer.postProcess(imageData);
-			ImageData newData = adaptImageDataIfDisabledOrGray(imageData);
-			return init(newData, zoom);
+			return zoomLevelToImageHandle.get(zoom);
 		} finally {
 			gc.dispose();
-			image.dispose();
 		}
 	}
 

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_graphics_Image.java

@@ -1075,6 +1075,39 @@ public void test_imageDataSameViaProviderAndSimpleData() {
 	dataImage.dispose();
 }
 
+@Test
+public void test_ImageWithImageGcDrawerWrapper() {
+	Image image = new Image(display, 16, 16);
+	GC gc = new GC(image);
+	gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
+	gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
+	gc.fillRectangle(0, 0, 16, 16);
+	gc.dispose();
+	image.getImageData().transparentPixel = display.getSystemColor(SWT.COLOR_BLACK).getAlpha();
+	ImageData imageDataForSimpleImageWithGcOperation = image.getImageData();
+
+	final ImageGcDrawer imageGcDrawerWithPostProcess = new ImageGcDrawer() {
+		@Override
+		public void drawOn(GC gc, int width, int height) {
+			gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
+			gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
+			gc.fillRectangle(0, 0, 16, 16);
+		}
+
+		@Override
+		public void postProcess(ImageData imageData) {
+			imageData.transparentPixel = display.getSystemColor(SWT.COLOR_BLACK).getAlpha();
+		}
+	};
+	Image imageWithGCDrawerWrapper = new Image(display, imageGcDrawerWithPostProcess, 16, 16);
+	ImageData imageDataForImageWithGcDrawer = imageWithGCDrawerWrapper.getImageData();
+
+	assertEquals(0, imageDataComparator().compare(imageDataForSimpleImageWithGcOperation, imageDataForImageWithGcDrawer));
+
+	image.dispose();
+	imageWithGCDrawerWrapper.dispose();
+}
+
 
 private Comparator<ImageData> imageDataComparator() {
 	return Comparator.<ImageData>comparingInt(d -> d.width) //