[FIXUP] Improve consideration of file- and target/device-zoom

Co-authored-by: Heiko Klare <[email protected]>

Author: HannesWell

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

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2020 IBM Corporation and others.
+ * Copyright (c) 2000, 2025 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -19,6 +19,7 @@
 
 import org.eclipse.swt.*;
 import org.eclipse.swt.internal.*;
+import org.eclipse.swt.internal.DPIUtil.*;
 import org.eclipse.swt.internal.cocoa.*;
 import org.eclipse.swt.internal.graphics.*;
 
@@ -692,6 +693,7 @@ public Image(Device device, InputStream stream) {
 	NSAutoreleasePool pool = null;
 	if (!NSThread.isMainThread()) pool = (NSAutoreleasePool) new NSAutoreleasePool().alloc().init();
 	try {
+		// TODO: scale SVGs here too?
 		init(new ImageData(stream));
 		init();
 	} finally {
@@ -738,6 +740,7 @@ public Image(Device device, String filename) {
 	try {
 		if (filename == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 		initNative(filename);
+		// TODO: scale SVGs here too?
 		if (this.handle == null) init(new ImageData(filename));
 		init();
 	} finally {
@@ -778,6 +781,7 @@ public Image(Device device, ImageFileNameProvider imageFileNameProvider) {
 	super(device);
 	if (imageFileNameProvider == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 	this.imageFileNameProvider = imageFileNameProvider;
+	//TODO: implement fine-grained zoom handling here as well?
 	String filename = imageFileNameProvider.getImagePath(100);
 	if (filename == null) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
 	NSAutoreleasePool pool = null;
@@ -792,6 +796,14 @@ public Image(Device device, ImageFileNameProvider imageFileNameProvider) {
 			id id = NSImageRep.imageRepWithContentsOfFile(NSString.stringWith(filename2x));
 			NSImageRep rep = new NSImageRep(id);
 			handle.addRepresentation(rep);
+		} else {
+			// Try to natively scale up the image (e.g. possible if it's an SVG)
+			ElementAtZoom<ImageData> imageData2x = ImageDataLoader.load(filename, 100, 200);
+			if (imageData2x.zoom() == 200) {
+				Image image2x = new Image(device, imageData2x.element());
+				NSImageRep rep = ImageUtil.createImageRep(image2x, image2x.width, image2x.height);
+				handle.addRepresentation(rep);
+			}
 		}
 	} finally {
 		if (pool != null) pool.release();
@@ -880,7 +892,7 @@ public Image(Device device, ImageGcDrawer imageGcDrawer, int width, int height)
 	if (!NSThread.isMainThread()) pool = (NSAutoreleasePool) new NSAutoreleasePool().alloc().init();
 	try {
 		init (data);
-		init ();		
+		init ();
 	} finally {
 		if (pool != null) pool.release();
 	}
@@ -1193,19 +1205,18 @@ NSBitmapImageRep getRepresentation (int scaleFactor) {
 	NSArray reps = handle.representations();
 	NSSize size = handle.size();
 	long count = reps.count();
-	NSSize targetSize = new NSSize();
-	targetSize.width = (int)size.width * scaleFactor / 100;
-	targetSize.height = (int)size.height * scaleFactor / 100;
+	int width = (int) size.width * scaleFactor / 100;
+	int height = (int) size.height * scaleFactor / 100;
 	NSBitmapImageRep rep;
 	for (int i = 0; i < count; i++) {
 		rep = new NSBitmapImageRep(reps.objectAtIndex(i));
-		if ((targetSize.width == rep.pixelsWide() && targetSize.height == rep.pixelsHigh())) {
+		if (width == rep.pixelsWide() && height == rep.pixelsHigh()) {
 			if (rep.isKindOfClass(OS.class_NSBitmapImageRep)) {
 				return rep;
 			}
 		}
 	}
-	NSBitmapImageRep newRep = createImageRep(targetSize);
+	NSBitmapImageRep newRep = createImageRep(width, height);
 	for (int i = 0; i < count; i++) {
 		handle.removeRepresentation(new NSImageRep(handle.representations().objectAtIndex(0)));
 	}
@@ -1397,8 +1408,8 @@ NSBitmapImageRep getRepresentation () {
 	return getRepresentation (DPIUtil.getDeviceZoom ());
 }
 
-NSBitmapImageRep createImageRep(NSSize targetSize) {
-	return ImageUtil.createImageRep(this, targetSize);
+NSBitmapImageRep createImageRep(int targetWidth, int targetHeight) {
+	return ImageUtil.createImageRep(this, targetWidth, targetHeight);
 }
 
 /**

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

@@ -14,13 +14,15 @@
 package org.eclipse.swt.graphics;
 
 import java.io.*;
+import java.util.*;
 
+import org.eclipse.swt.internal.DPIUtil.*;
 import org.eclipse.swt.internal.image.*;
 
 class InternalImageLoader {
 
-	static ImageData[] load(InputStream stream, ImageLoader imageLoader, int zoom) {
-		return FileFormat.load(stream, imageLoader, zoom);
+	static List<ElementAtZoom<ImageData>> load(InputStream stream, ImageLoader imageLoader, int fileZoom, int targetZoom) {
+		return FileFormat.load(stream, imageLoader, fileZoom, targetZoom);
 	}
 
 	static void save(OutputStream stream, int format, ImageLoader imageLoader) {

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/internal/graphics/ImageUtil.java

@@ -28,25 +28,25 @@ public class ImageUtil {
 	 * Creates new image representation based on the source image.
 	 *
 	 * @param image      Source image object
-	 * @param targetSize the size at which image representation needs to be created
+	 * @param targetWidth the width at which image representation needs to be created
+	 * @param targetHeight the height at which image representation needs to be created
 	 *
 	 * @return image representation
 	 *
 	 * @since 3.110
 	 */
-	public static NSBitmapImageRep createImageRep(Image image, NSSize targetSize) {
-		NSBitmapImageRep rep;
+	public static NSBitmapImageRep createImageRep(Image image, int targetWidth, int targetHeight) {
 		NSImage imgHandle= image.handle;
-		rep = (NSBitmapImageRep)new NSBitmapImageRep().alloc();
-		rep = rep.initWithBitmapDataPlanes(0, (int) targetSize.width, (int) targetSize.height, 8, 4, true, false, OS.NSDeviceRGBColorSpace, OS.NSAlphaFirstBitmapFormat, (int) targetSize.width * 4, 32);
-		C.memset(rep.bitmapData(), 0xFF, (int) targetSize.width * (int)targetSize.height * 4);
+		NSBitmapImageRep rep = (NSBitmapImageRep) new NSBitmapImageRep().alloc();
+		rep = rep.initWithBitmapDataPlanes(0, targetWidth, targetHeight, 8, 4, true, false, OS.NSDeviceRGBColorSpace, OS.NSAlphaFirstBitmapFormat, targetWidth * 4, 32);
+		C.memset(rep.bitmapData(), 0xFF, targetWidth * targetHeight * 4);
 		NSGraphicsContext context = NSGraphicsContext.graphicsContextWithBitmapImageRep(rep);
 		NSGraphicsContext.static_saveGraphicsState();
 		context.setImageInterpolation(OS.NSImageInterpolationHigh);
 		NSGraphicsContext.setCurrentContext(context);
 		NSRect target = new NSRect();
-		target.width = targetSize.width;
-		target.height = targetSize.height;
+		target.width = targetWidth;
+		target.height = targetHeight;
 		NSRect sourceRect = new NSRect();
 		sourceRect.width = 0;
 		sourceRect.height = 0;

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Canvas.java

@@ -183,7 +183,7 @@ void drawWidget (long id, NSGraphicsContext context, NSRect rect) {
 		if (image != null) {
 			NSImage imageHandle = image.handle;
 			NSSize size = imageHandle.size();
-			NSImageRep imageRep = ImageUtil.createImageRep(image, size);
+			NSImageRep imageRep = ImageUtil.createImageRep(image, (int) size.width, (int) size.height);
 			if (!imageRep.isKindOfClass(OS.class_NSBitmapImageRep)) return;
 			NSBitmapImageRep rep = new NSBitmapImageRep(imageRep);
 			CGRect destRect = new CGRect ();

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

@@ -331,9 +331,7 @@ scanlinePad, checkData(data), 0, null,
  * @see ImageLoader#load(InputStream)
  */
 public ImageData(InputStream stream) {
-	ImageData[] data = ImageDataLoader.load(stream);
-	if (data.length < 1) SWT.error(SWT.ERROR_INVALID_IMAGE);
-	ImageData i = data[0];
+	ImageData i = ImageDataLoader.load(stream);
 	setAllFields(
 		i.width,
 		i.height,
@@ -377,9 +375,7 @@ public ImageData(InputStream stream) {
  * </ul>
  */
 public ImageData(String filename) {
-	ImageData[] data = ImageDataLoader.load(filename);
-	if (data.length < 1) SWT.error(SWT.ERROR_INVALID_IMAGE);
-	ImageData i = data[0];
+	ImageData i = ImageDataLoader.load(filename);
 	setAllFields(
 		i.width,
 		i.height,

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

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2006 IBM Corporation and others.
+ * Copyright (c) 2000, 2025 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -14,19 +14,39 @@
 package org.eclipse.swt.graphics;
 
 import java.io.*;
+import java.util.*;
+
+import org.eclipse.swt.*;
+import org.eclipse.swt.internal.DPIUtil.*;
 
 /**
  * Internal class that separates ImageData from ImageLoader
  * to allow removal of ImageLoader from the toolkit.
  */
 class ImageDataLoader {
 
-	public static ImageData[] load(InputStream stream) {
-		return new ImageLoader().load(stream);
+	public static ImageData load(InputStream stream) {
+		ImageData[] data = new ImageLoader().load(stream);
+		if (data.length < 1) SWT.error(SWT.ERROR_INVALID_IMAGE);
+		return data[0];
+	}
+
+	public static ImageData load(String filename) {
+		ImageData[] data = new ImageLoader().load(filename);
+		if (data.length < 1) SWT.error(SWT.ERROR_INVALID_IMAGE);
+		return data[0];
+	}
+
+	public static ElementAtZoom<ImageData> load(InputStream stream, int fileZoom, int targetZoom) {
+		List<ElementAtZoom<ImageData>> data = new ImageLoader().load(stream, fileZoom, targetZoom);
+		if (data.isEmpty()) SWT.error(SWT.ERROR_INVALID_IMAGE);
+		return data.get(0);
 	}
 
-	public static ImageData[] load(String filename) {
-		return new ImageLoader().load(filename);
+	public static ElementAtZoom<ImageData> load(String filename, int fileZoom, int targetZoom) {
+		List<ElementAtZoom<ImageData>> data = new ImageLoader().load(filename, fileZoom, targetZoom);
+		if (data.isEmpty()) SWT.error(SWT.ERROR_INVALID_IMAGE);
+		return data.get(0);
 	}
 
 }

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

@@ -18,6 +18,7 @@
 import java.util.*;
 
 import org.eclipse.swt.*;
+import org.eclipse.swt.internal.DPIUtil.*;
 import org.eclipse.swt.internal.image.*;
 
 /**
@@ -149,10 +150,16 @@ void reset() {
  * </ul>
  */
 public ImageData[] load(InputStream stream) {
+	load(stream, FileFormat.DEFAULT_ZOOM, FileFormat.DEFAULT_ZOOM);
+	return data;
+}
+
+List<ElementAtZoom<ImageData>> load(InputStream stream, int fileZoom, int targetZoom) {
 	if (stream == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 	reset();
-	data = InternalImageLoader.load(stream, this, FileFormat.DEFAULT_ZOOM);
-	return data;
+	List<ElementAtZoom<ImageData>> images = InternalImageLoader.load(stream, this, fileZoom, targetZoom);
+	data = images.stream().map(ElementAtZoom::element).toArray(ImageData[]::new);
+	return images;
 }
 
 /**
@@ -174,9 +181,14 @@ public ImageData[] load(InputStream stream) {
  * </ul>
  */
 public ImageData[] load(String filename) {
+	load(filename, FileFormat.DEFAULT_ZOOM, FileFormat.DEFAULT_ZOOM);
+	return data;
+}
+
+List<ElementAtZoom<ImageData>> load(String filename, int fileZoom, int targetZoom) {
 	if (filename == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
 	try (InputStream stream = new FileInputStream(filename)) {
-		return load(stream);
+		return load(stream, fileZoom, targetZoom);
 	} catch (IOException e) {
 		SWT.error(SWT.ERROR_IO, e);
 	}

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/image/FileFormat.java

@@ -20,7 +20,7 @@
 
 import org.eclipse.swt.*;
 import org.eclipse.swt.graphics.*;
-import org.eclipse.swt.internal.*;
+import org.eclipse.swt.internal.DPIUtil.*;
 
 /**
  * Abstract factory class for loading/unloading images from files or streams
@@ -57,20 +57,30 @@ public abstract class FileFormat {
 
 	public static final int DEFAULT_ZOOM = 100;
 
+	private static Optional<FileFormat> determineFileFormat(LEDataInputStream stream) {
+		return FORMAT_FACTORIES.stream().skip(1).map(Supplier::get).filter(f -> {
+			try {
+				return f.isFileFormat(stream);
+			} catch (IOException e) {
+				return false;
+			}
+		}).findFirst();
+	}
+
+	private static final int MAX_SIGNATURE_BYTES = 18 + 2; // e.g. Win-BMP or OS2-BMP plus a safety-margin
+
+	public static boolean isDynamicallySizableFormat(InputStream is) {
+		Optional<FileFormat> format = determineFileFormat(new LEDataInputStream(is, MAX_SIGNATURE_BYTES));
+		return format.isPresent() && !(format.get() instanceof StaticImageFileFormat);
+	}
+
 	static abstract class StaticImageFileFormat extends FileFormat {
 
 		abstract ImageData[] loadFromByteStream();
 
 		@Override
-		ImageData[] loadFromByteStream(int zoom) {
-			if (zoom == DEFAULT_ZOOM) {
-				return loadFromByteStream();
-			}
-			return Arrays.stream(loadFromByteStream()).map(data -> {
-				int width = DPIUtil.scaleUp(data.width, zoom);
-				int height = DPIUtil.scaleUp(data.height, zoom);
-				return data.scaledTo(width, height);
-			}).toArray(ImageData[]::new);
+		List<ElementAtZoom<ImageData>> loadFromByteStream(int fileZoom, int targetZoom) {
+			return Arrays.stream(loadFromByteStream()).map(d -> new ElementAtZoom<>(d, fileZoom)).toList();
 		}
 	}
 
@@ -85,16 +95,20 @@ ImageData[] loadFromByteStream(int zoom) {
 	 */
 	abstract boolean isFileFormat(LEDataInputStream stream) throws IOException;
 
-	abstract ImageData[] loadFromByteStream(int zoom);
+	/**
+	 * Format that do not implement {@link StaticImageFileFormat} MUST return
+	 * {@link ImageData} with the specified {@code targetZoom}.
+	 */
+	abstract List<ElementAtZoom<ImageData>> loadFromByteStream(int fileZoom, int targetZoom);
 
 /**
  * Read the specified input stream, and return the
  * device independent image array represented by the stream.
  */
-public ImageData[] loadFromStream(LEDataInputStream stream, int zoom) {
+public List<ElementAtZoom<ImageData>> loadFromStream(LEDataInputStream stream, int fileZoom, int targetZoom) {
 	try {
 		inputStream = stream;
-		return loadFromByteStream(zoom);
+		return loadFromByteStream(fileZoom, targetZoom);
 	} catch (Exception e) {
 		if (e instanceof IOException) {
 			SWT.error(SWT.ERROR_IO, e);
@@ -109,20 +123,14 @@ public ImageData[] loadFromStream(LEDataInputStream stream, int zoom) {
  * Read the specified input stream using the specified loader, and
  * return the device independent image array represented by the stream.
  */
-public static ImageData[] load(InputStream is, ImageLoader loader, int zoom) {
+public static List<ElementAtZoom<ImageData>> load(InputStream is, ImageLoader loader, int fileZoom, int targetZoom) {
 	LEDataInputStream stream = new LEDataInputStream(is);
-	FileFormat fileFormat = FORMAT_FACTORIES.stream().skip(1) //
-			.map(Supplier::get).filter(f -> {
-				try {
-					return f.isFileFormat(stream);
-				} catch (IOException e) {
-					return false;
-				}
-			}) //
-			.findFirst().orElse(null);
-	if (fileFormat == null) SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
+	FileFormat fileFormat = determineFileFormat(stream).orElseGet(() -> {
+		SWT.error(SWT.ERROR_UNSUPPORTED_FORMAT);
+		return null;
+	});
 	fileFormat.loader = loader;
-	return fileFormat.loadFromStream(stream, zoom);
+	return fileFormat.loadFromStream(stream, fileZoom, targetZoom);
 }
 
 /**

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/image/WinICOFileFormat.java

@@ -133,7 +133,7 @@ ImageData loadIcon(int[] iconHeader) {
 		StaticImageFileFormat png = new PNGFileFormat();
 		if (png.isFileFormat(inputStream)) {
 			png.loader = this.loader;
-			return png.loadFromStream(inputStream, DEFAULT_ZOOM)[0];
+			return png.loadFromStream(inputStream, DEFAULT_ZOOM, DEFAULT_ZOOM).get(0).element();
 		}
 	} catch (Exception e) {
 	}