GC#DrawImage(image, destX, destY, destWidth, destHeight) now tries to load images at the requested destination size before drawing

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

@@ -1818,23 +1818,21 @@ public String toString () {
  *
  * @param gc the GC to draw on the resulting image
  * @param imageData the imageData which is used to draw the scaled Image
- * @param width the width of the original image
- * @param height the height of the original image
- * @param scaleFactor the factor with which the image is supposed to be scaled
+ * @param width the width to which the image is supposed to be scaled
+ * @param height the height to which the image is supposed to be scaled
  *
  * @noreference This method is not intended to be referenced by clients.
  */
-public static void drawScaled(GC gc, ImageData imageData, int width, int height, float scaleFactor) {
+public static void drawAtSize(GC gc, ImageData imageData, int width, int height) {
 	StrictChecks.runWithStrictChecksDisabled(() -> {
 		Image imageToDraw = new Image(gc.device, (ImageDataProvider) zoom -> imageData);
-		gc.drawImage(imageToDraw, 0, 0, CocoaDPIUtil.pixelToPoint(width), CocoaDPIUtil.pixelToPoint(height),
+		gc.drawImage(imageToDraw, 0, 0, CocoaDPIUtil.pixelToPoint(imageData.width), CocoaDPIUtil.pixelToPoint(imageData.height),
 				/*
 				 * E.g. destWidth here is effectively DPIUtil.autoScaleDown (scaledWidth), but
 				 * avoiding rounding errors. Nevertheless, we still have some rounding errors
 				 * due to the point-based API GC#drawImage(..).
 				 */
-				0, 0, Math.round(CocoaDPIUtil.pixelToPoint(width * scaleFactor)),
-				Math.round(CocoaDPIUtil.pixelToPoint(height * scaleFactor)));
+				0, 0,  Math.round(CocoaDPIUtil.pixelToPoint(width)),  Math.round(CocoaDPIUtil.pixelToPoint(height)));
 		imageToDraw.dispose();
 	});
 }

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/ImageDataAtSizeProvider.java

@@ -0,0 +1,49 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Vector Informatik GmbH and others.
+ *
+ * This program and the accompanying materials are made available under the terms of the Eclipse
+ * Public License 2.0 which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Michael Bangas (Vector Informatik GmbH) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.graphics;
+
+/**
+ * Provides an API that is invoked by SWT when an image needs to be drawn at a
+ * specified width and height.
+ * <p>
+ * Client code must implement this interface to supply {@link ImageData} on demand.
+ * </p>
+ *
+ * @since 3.132
+ * @noreference This class is still experimental API and might be subject to change.
+ */
+public interface ImageDataAtSizeProvider extends ImageDataProvider {
+
+	/**
+	 * Returns the {@link ImageData} for the given width and height.
+	 *
+	 * <p>
+	 * <b>Implementation notes:</b>
+	 * </p>
+	 * <ul>
+	 * <li>Returning <code>null</code> is not permitted. If <code>null</code> is
+	 * returned, SWT will throw an exception when loading the image.</li>
+	 * <li>The returned {@link ImageData} must match the requested width and height
+	 * exactly. Implementations should ensure proper resizing and scaling of the
+	 * image based on the height and width requested</li>
+	 * </ul>
+	 *
+	 * @param width  the desired width of the {@link ImageData} to be returned
+	 * @param height the desired height of the {@link ImageData} to be returned
+	 * @return the {@link ImageData} that exactly matches the requested width and
+	 *         height
+	 * @since 3.132
+	 */
+	ImageData getImageData(int width, int height);
+
+}

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/ImageDataLoader.java

@@ -45,6 +45,14 @@ public static boolean canLoadAtZoom(String filename, int fileZoom, int targetZoo
 		return ImageLoader.canLoadAtZoom(filename, fileZoom, targetZoom);
 	}
 
+	static boolean isDynamicallySizable(String filename) {
+		return ImageLoader.isDynamicallySizable(filename);
+	}
+
+	static boolean isDynamicallySizable(InputStream stream) {
+		return ImageLoader.isDynamicallySizable(stream);
+	}
+
 	public static ElementAtZoom<ImageData> loadByZoom(InputStream stream, int fileZoom, int targetZoom) {
 		List<ElementAtZoom<ImageData>> data = new ImageLoader().loadByZoom(stream, fileZoom, targetZoom);
 		if (data.isEmpty()) SWT.error(SWT.ERROR_INVALID_IMAGE);

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/ImageLoader.java

@@ -229,6 +229,19 @@ static boolean canLoadAtZoom(String filename, int fileZoom, int targetZoom) {
 	return false;
 }
 
+static boolean isDynamicallySizable(String filename) {
+	try (InputStream stream = new FileInputStream(filename)) {
+		return FileFormat.isDynamicallySizableFormat(stream);
+	} catch (IOException e) {
+		SWT.error(SWT.ERROR_IO, e);
+	}
+	return false;
+}
+
+static boolean isDynamicallySizable(InputStream stream) {
+	return FileFormat.isDynamicallySizableFormat(stream);
+}
+
 /**
  * Saves the image data in this ImageLoader to the specified stream.
  * The format parameter can have one of the following values:

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

@@ -146,14 +146,24 @@ public static ImageData autoScaleImageData (Device device, final ImageData image
 	int height = imageData.height;
 	int scaledWidth = Math.round (width * scaleFactor);
 	int scaledHeight = Math.round (height * scaleFactor);
+	return scaleImage(device, imageData, Image::drawAtSize, scaledWidth, scaledHeight);
+}
+
+@FunctionalInterface
+private interface ImageDrawFunction {
+	void draw(GC gc, ImageData imageData, int width, int height);
+}
+
+private static ImageData scaleImage(Device device, final ImageData imageData, ImageDrawFunction drawFunction,
+		int scaledWidth, int scaledHeight) {
 	int defaultZoomLevel = 100;
 	boolean useSmoothScaling = isSmoothScalingEnabled() && imageData.getTransparencyType() != SWT.TRANSPARENCY_MASK;
 	if (useSmoothScaling) {
 		ImageGcDrawer drawer =  new ImageGcDrawer() {
 			@Override
 			public void drawOn(GC gc, int imageWidth, int imageHeight) {
 				gc.setAntialias (SWT.ON);
-				Image.drawScaled(gc, imageData, width, height, scaleFactor);
+				drawFunction.draw(gc, imageData, imageWidth, imageHeight);
 			};
 
 			@Override
@@ -170,6 +180,10 @@ public int getGcStyle() {
 	}
 }
 
+public static ImageData autoScaleImageData(Device device, final ImageData imageData, int targetWidth, int targetHeight) {
+	return scaleImage(device, imageData, Image::drawAtSize, targetWidth, targetHeight);
+}
+
 public static boolean isSmoothScalingEnabled() {
 	return autoScaleMethod == AutoScaleMethod.SMOOTH;
 }

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

@@ -1579,22 +1579,21 @@ public String toString () {
  *
  * @param gc the GC to draw on the resulting image
  * @param imageData the imageData which is used to draw the scaled Image
- * @param width the width of the original image
- * @param height the height of the original image
- * @param scaleFactor the factor with which the image is supposed to be scaled
+ * @param width the width to which the image is supposed to be scaled
+ * @param height the height to which the image is supposed to be scaled
  *
  * @noreference This method is not intended to be referenced by clients.
  */
-public static void drawScaled(GC gc, ImageData imageData, int width, int height, float scaleFactor) {
+public static void drawAtSize(GC gc, ImageData imageData, int width, int height) {
 	StrictChecks.runWithStrictChecksDisabled(() -> {
 		Image imageToDraw = new Image(gc.device, (ImageDataProvider) zoom -> imageData);
-		gc.drawImage(imageToDraw, 0, 0, width, height,
+		gc.drawImage(imageToDraw, 0, 0, imageData.width, imageData.height,
 				/*
 				 * E.g. destWidth here is effectively DPIUtil.autoScaleDown (scaledWidth), but
 				 * avoiding rounding errors. Nevertheless, we still have some rounding errors
 				 * due to the point-based API GC#drawImage(..).
 				 */
-				0, 0, Math.round(width * scaleFactor), Math.round(height * scaleFactor));
+				0, 0, width, height);
 		imageToDraw.dispose();
 	});
 }

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

@@ -1061,7 +1061,8 @@ void apply() {
 
 	private void drawImageInPixels(Image image, Point location) {
 		if (image.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
-		drawImage(image, 0, 0, -1, -1, location.x, location.y, -1, -1, true, getZoom());
+		long handle = Image.win32_getHandle(image, getZoom());
+		drawImage(image, 0, 0, -1, -1, location.x, location.y, -1, -1, true, handle);
 	}
 }
 
@@ -1157,8 +1158,7 @@ public void drawImage(Image image, int destX, int destY, int destWidth, int dest
 		SWT.error(SWT.ERROR_INVALID_ARGUMENT);
 	}
 
-	storeAndApplyOperationForExistingHandle(new DrawScalingImageToImageOperation(image, new Rectangle(0, 0, 0, 0),
-			new Rectangle(destX, destY, destWidth, destHeight)));
+	storeAndApplyOperationForExistingHandle(new DrawScaledImageOperation(image, new Rectangle(destX, destY, destWidth, destHeight)));
 }
 
 void drawImage(Image srcImage, int srcX, int srcY, int srcWidth, int srcHeight, int destX, int destY, int destWidth, int destHeight, boolean simple) {
@@ -1216,6 +1216,29 @@ private int calculateZoomForImage(int gcZoom, int srcWidth, int srcHeight, int d
 	}
 }
 
+private class DrawScaledImageOperation extends ImageOperation {
+	private final Rectangle destination;
+
+	DrawScaledImageOperation(Image image, Rectangle destination) {
+		super(image);
+		this.destination = destination;
+	}
+
+	@Override
+	void apply() {
+		int gcZoom = getZoom();
+		drawImage(getImage(), destination.x, destination.y, destination.width, destination.height, gcZoom);
+	}
+}
+
+private void drawImage(Image image, int destX, int destY, int destWidth, int destHeight, int imageZoom) {
+	Rectangle destPixels = Win32DPIUtils.pointToPixel(drawable, new Rectangle(destX, destY, destWidth, destHeight), imageZoom);
+	image.executeOnImageHandleAtSize((tempHandle, handleSize) -> {
+		drawImage(image, 0, 0, handleSize.x, handleSize.y, destPixels.x, destPixels.y, destPixels.width,
+				destPixels.height, false, tempHandle);
+	}, destPixels.width, destPixels.height);
+}
+
 private void drawImage(Image image, int srcX, int srcY, int srcWidth, int srcHeight, int destX, int destY,
 		int destWidth, int destHeight, int imageZoom, int scaledImageZoom) {
 	Rectangle src = Win32DPIUtils.pointToPixel(drawable, new Rectangle(srcX, srcY, srcWidth, srcHeight), scaledImageZoom);
@@ -1237,7 +1260,7 @@ private void drawImage(Image image, int srcX, int srcY, int srcWidth, int srcHei
 			}
 		}
 	}
-	drawImage(image, src.x, src.y, src.width, src.height, dest.x, dest.y, dest.width, dest.height, false, scaledImageZoom);
+	drawImage(image, src.x, src.y, src.width, src.height, dest.x, dest.y, dest.width, dest.height, false, image.getHandle(scaledImageZoom, data.nativeZoom));
 }
 
 private class DrawImageToImageOperation extends ImageOperation {
@@ -1254,17 +1277,19 @@ private class DrawImageToImageOperation extends ImageOperation {
 
 	@Override
 	void apply() {
-		drawImage(getImage(), source.x, source.y, source.width, source.height, destination.x, destination.y, destination.width, destination.height, simple, getZoom());
+		long handle = Image.win32_getHandle(getImage(), getZoom());
+		drawImage(getImage(), source.x, source.y, source.width, source.height, destination.x, destination.y, destination.width, destination.height, simple, handle);
 	}
 }
 
-private void drawImage(Image srcImage, int srcX, int srcY, int srcWidth, int srcHeight, int destX, int destY, int destWidth, int destHeight, boolean simple, int imageZoom) {
+private void drawImage(Image srcImage, int srcX, int srcY, int srcWidth, int srcHeight, int destX, int destY, int destWidth, int destHeight, boolean simple, long tempImageHandle) {
 	if (data.gdipGraphics != 0) {
 		//TODO - cache bitmap
-		long [] gdipImage = srcImage.createGdipImage(imageZoom);
+		long [] gdipImage = srcImage.createGdipImageFromHandle(tempImageHandle);
 		long img = gdipImage[0];
 		int imgWidth = Gdip.Image_GetWidth(img);
 		int imgHeight = Gdip.Image_GetHeight(img);
+
 		if (srcWidth == 0 && srcHeight == 0) {
 			srcWidth = imgWidth;
 			srcHeight = imgHeight;
@@ -1319,13 +1344,13 @@ private void drawImage(Image srcImage, int srcX, int srcY, int srcWidth, int src
 		}
 		return;
 	}
-	long imageHandle = srcImage.getHandle(imageZoom, data.nativeZoom);
 	switch (srcImage.type) {
 		case SWT.BITMAP:
-			drawBitmap(srcImage, imageHandle, srcX, srcY, srcWidth, srcHeight, destX, destY, destWidth, destHeight, simple);
+			drawBitmap(srcImage, tempImageHandle, srcX, srcY, srcWidth, srcHeight, destX, destY, destWidth, destHeight,
+					simple);
 			break;
 		case SWT.ICON:
-			drawIcon(imageHandle, srcX, srcY, srcWidth, srcHeight, destX, destY, destWidth, destHeight, simple);
+			drawIcon(tempImageHandle, srcX, srcY, srcWidth, srcHeight, destX, destY, destWidth, destHeight, simple);
 			break;
 	}
 }