diff --git a/examples/org.eclipse.swt.snippets/Snippets.md b/examples/org.eclipse.swt.snippets/Snippets.md index 4251fb9d051..042beb3cd13 100644 --- a/examples/org.eclipse.swt.snippets/Snippets.md +++ b/examples/org.eclipse.swt.snippets/Snippets.md @@ -217,6 +217,7 @@ To contribute a new snippet, [create a snippet contribution as a pull request](h - [draw a disabled/grayed image at various zoom levels](https://github.com/eclipse-platform/eclipse.platform.swt/tree/master/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet382.java) – [(preview)](https://github.com/eclipse-platform/eclipse.platform.swt/blob/master/examples/org.eclipse.swt.snippets/previews/Snippet382.png "Preview for Snippet 382") - [compare algorithms for rendering disabled images](https://github.com/eclipse-platform/eclipse.platform.swt/tree/master/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet384.java) – [(preview)](https://github.com/eclipse-platform/eclipse.platform.swt/blob/master/examples/org.eclipse.swt.snippets/previews/Snippet384.png "Preview for Snippet 384") - [draw an image with watermark using ImageGcProvider](https://github.com/eclipse-platform/eclipse.platform.swt/tree/master/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet385.java) – [(preview)](https://github.com/eclipse-platform/eclipse.platform.swt/blob/master/examples/org.eclipse.swt.snippets/previews/Snippet385.png "Preview for Snippet 385") +- [options for programmatically creating an image](https://github.com/eclipse-platform/eclipse.platform.swt/tree/master/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet387.java) – [(preview)](https://github.com/eclipse-platform/eclipse.platform.swt/blob/master/examples/org.eclipse.swt.snippets/previews/Snippet387.png "Preview for Snippet 387") ### **ImageData** - [display an animated GIF](https://github.com/eclipse-platform/eclipse.platform.swt/tree/master/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet141.java) diff --git a/examples/org.eclipse.swt.snippets/previews/Snippet387.png b/examples/org.eclipse.swt.snippets/previews/Snippet387.png new file mode 100644 index 00000000000..a2adfe8fabd Binary files /dev/null and b/examples/org.eclipse.swt.snippets/previews/Snippet387.png differ diff --git a/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet387.java b/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet387.java new file mode 100644 index 00000000000..d6e61cea1ac --- /dev/null +++ b/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet387.java @@ -0,0 +1,112 @@ +/******************************************************************************* + * 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 + *******************************************************************************/ +package org.eclipse.swt.snippets; + +import org.eclipse.swt.graphics.*; +import org.eclipse.swt.widgets.*; + +/** + * Demonstrates different ways of programmatically creating an image with a GC + *

+ * When creating an image programmatically, it is important to use an + * appropriate way of doing that when at the time of image creation it is not + * yet known at which zoom the image will be used. This is particularly the case + * when using monitor-specific scaling on Windows. + *

+ * There are two general options how to programmatically create an image: + *

+ * When using the second approach creating a {@link GC} on top of an image, it + * is important to not dispose the GC before using the image, as in that case + * the Windows implementation of an image can request its regeneration at the + * desired zoom from the GC. If the GC is disposed before the image is used at + * desired zoom, it may need to blurry-scale any existing drawing result to the + * requested zoom instead of sharply rendering it at that zoom. + *

+ * This snippet demonstrates both proper usages of the above mentioned options + * as well as a usage that disposes the GC before consuming the image at the + * desired zoom, leading to a blurry result. To see such a bad result, the + * snippet needs to be executed on Windows and has to be moved between monitors + * with different monitor zooms. + *

+ * For a list of all SWT example snippets see + * http://www.eclipse.org/swt/snippets/ + *

+ */ +public class Snippet387 { + + private static final int PADDING = 5; + private static final int IMAGE_WIDTH = 270; + private static final int IMAGE_HEIGHT = 50; + + public static void main(String[] args) { + activateMonitorSpecificScaling(); + + Display display = new Display(); + Shell shell = new Shell(display); + shell.setText("Programmatic Images"); + shell.setSize(IMAGE_WIDTH + 2 * PADDING + 20, 3 * IMAGE_HEIGHT + 4 * PADDING + 40); + + Image staticImage = createStaticImage(display, "Static Image with disposed GC", true); + Image staticImageUndisposedGC = createStaticImage(display, "Static Image with non-disposed GC", false); + Image dynamicImage = createDynamicImage(display, "Dynamic Image"); + + shell.addPaintListener(event -> { + GC gc = event.gc; + gc.drawImage(staticImage, PADDING, PADDING); + gc.drawImage(staticImageUndisposedGC, PADDING, 2 * PADDING + IMAGE_HEIGHT); + gc.drawImage(dynamicImage, PADDING, 3 * PADDING + 2 * IMAGE_HEIGHT); + }); + + shell.open(); + while (!shell.isDisposed()) { + if (!display.readAndDispatch()) { + display.sleep(); + } + } + display.dispose(); + } + + private static void activateMonitorSpecificScaling() { + System.setProperty("swt.autoScale.updateOnRuntime", "true"); + } + + private static Image createStaticImage(Display display, String text, boolean disposeGC) { + Image staticImage = new Image(display, IMAGE_WIDTH, IMAGE_HEIGHT); + GC imageGC = new GC(staticImage); + try { + drawImageContent(imageGC, text, IMAGE_WIDTH, IMAGE_HEIGHT); + } finally { + if (disposeGC) { + imageGC.dispose(); + } + } + return staticImage; + } + + private static Image createDynamicImage(Display display, String text) { + return new Image(display, (gc, w, h) -> drawImageContent(gc, text, w, h), IMAGE_WIDTH, IMAGE_HEIGHT); + } + + private static void drawImageContent(GC gc, String text, int width, int height) { + gc.drawRectangle(0, 0, width - 1, height - 1); + gc.drawText(text, PADDING, PADDING); + } + +} \ No newline at end of file