Use ImageGcDrawer for smooth scaling of ImageData

This commit adapts the smooth scaling implementation to use
ImageGcDrawer.

Author: akoch-yatta

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

@@ -903,8 +903,16 @@ public Image(Device device, ImageGcDrawer imageGcDrawer, int width, int height)
 }
 
 private ImageData drawWithImageGcDrawer(ImageGcDrawer imageGcDrawer, int width, int height, int zoom) {
-	Image image = new Image(device, width, height);
-	GC gc = new GC(image);
+	int gcStyle = imageGcDrawer.getGcStyle();
+	Image image;
+	if ((gcStyle & SWT.TRANSPARENT) != 0) {
+		final ImageData resultData = new ImageData (width, height, 24, new PaletteData (0xFF, 0xFF00, 0xFF0000));
+		resultData.alphaData = new byte [width * height];
+		image = new Image(device, resultData);
+	} else {
+		image = new Image(device, width, height);
+	}
+	GC gc = new GC(image, gcStyle);
 	try {
 		imageGcDrawer.drawOn(gc, width, height);
 		ImageData imageData = image.getImageData(zoom);

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java

@@ -306,16 +306,21 @@ private static ImageData autoScaleImageData (Device device, final ImageData imag
 	boolean useSmoothScaling = isSmoothScalingEnabled() && imageData.getTransparencyType() != SWT.TRANSPARENCY_MASK;
 	if (useSmoothScaling) {
 		Image original = new Image (device, (ImageDataProvider) zoom -> imageData);
-		/* 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 resultImage = new Image (device, (ImageDataProvider) zoom -> resultData);
-		GC gc = new GC (resultImage);
-		gc.setAntialias (SWT.ON);
-		Image.drawScaled(gc, original, width, height, scaleFactor);
-		gc.dispose ();
+		ImageGcDrawer drawer =  new ImageGcDrawer() {
+			@Override
+			public void drawOn(GC gc, int imageWidth, int imageHeight) {
+				gc.setAntialias (SWT.ON);
+				Image.drawScaled(gc, original, width, height, scaleFactor);
+			};
+
+			@Override
+			public int getGcStyle() {
+				return SWT.TRANSPARENT;
+			}
+		};
+		Image resultImage = new Image (device, drawer, scaledWidth, scaledHeight);
+		ImageData result = resultImage.getImageData (100);
 		original.dispose ();
-		ImageData result = resultImage.getImageData (getDeviceZoom ());
 		resultImage.dispose ();
 		return result;
 	} else {

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

@@ -437,11 +437,14 @@ public Image(Device device, Rectangle bounds) {
  * @see #dispose()
  */
 public Image(Device device, ImageData data) {
+	this(device, DPIUtil.autoScaleUp(device, data), DPIUtil.getDeviceZoom());
+}
+
+private Image(Device device, ImageData data, int zoom) {
 	super(device);
 	if (data == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
-	currentDeviceZoom = DPIUtil.getDeviceZoom();
-	data = DPIUtil.autoScaleUp (device, data);
-	init(data);
+	currentDeviceZoom = zoom;
+	init(data, zoom);
 	init();
 }
 
@@ -695,9 +698,9 @@ public Image(Device device, ImageGcDrawer imageGcDrawer, int width, int height)
 		SWT.error(SWT.ERROR_NULL_ARGUMENT);
 	}
 	this.imageGcDrawer = imageGcDrawer;
-	currentDeviceZoom = DPIUtil.getDeviceZoom();
+	currentDeviceZoom = 100;
 	ImageData imageData = drawWithImageGcDrawer(width, height, currentDeviceZoom);
-	init (imageData);
+	init (imageData, currentDeviceZoom);
 	init ();
 }
 
@@ -1162,8 +1165,16 @@ public ImageData getImageData (int zoom) {
 }
 
 private ImageData drawWithImageGcDrawer(int width, int height, int zoom) {
-	Image image = new Image(device, width, height);
-	GC gc = new GC(image);
+	int gcStyle = imageGcDrawer.getGcStyle();
+	Image image;
+	if ((gcStyle & SWT.TRANSPARENT) != 0) {
+		final ImageData resultData = new ImageData(width, height, 24, new PaletteData (0xFF, 0xFF00, 0xFF0000));
+		resultData.alphaData = new byte [width * height];
+		image = new Image(device, resultData, zoom);
+	} else {
+		image = new Image(device, width, height);
+	}
+	GC gc = new GC(image, gcStyle);
 	try {
 		imageGcDrawer.drawOn(gc, width, height);
 		ImageData imageData = image.getImageData(zoom);
@@ -1274,6 +1285,10 @@ void init(int width, int height) {
 }
 
 void init(ImageData image) {
+	init(image, DPIUtil.getDeviceZoom());
+}
+
+void init(ImageData image, int zoom) {
 	if (image == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 
 	PaletteData palette = image.palette;
@@ -1286,7 +1301,7 @@ void init(ImageData image) {
 	int imageDataHeight = image.height;
 
 	// Scale dimensions of Image object to 100% scale factor
-	double scaleFactor = DPIUtil.getDeviceZoom() / 100f;
+	double scaleFactor = zoom / 100f;
 	this.width = (int) Math.round(imageDataWidth / scaleFactor);
 	this.height = (int) Math.round(imageDataHeight / scaleFactor);
 

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

@@ -378,7 +378,7 @@ private Image(Device device, ImageData data, int zoom) {
 	super(device);
 	if (data == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 	initialNativeZoom = zoom;
-	this.imageProvider = new PlainImageDataProviderWrapper(data);
+	this.imageProvider = new PlainImageDataProviderWrapper(data, zoom);
 	init();
 	this.device.registerResourceWithZoomSupport(this);
 }