Create custom cursor for 100%, 150% and 200% zoom #872

org.eclipse.gef/src/org/eclipse/gef/SharedCursors.java

@@ -60,7 +60,13 @@ private static Cursor createCursor(String sourceName) {
 		if (ImageUtils.isSvgSupported()) {
 			ImageDescriptor src1 = InternalImages.createDescriptor(sourceName);
 			ImageDescriptor src2 = InternalCursor.getCursorDescriptor();
-			ImageDescriptor src = new DecorationOverlayIcon(src1, src2, IDecoration.TOP_LEFT);
+			ImageDescriptor src = new DecorationOverlayIcon(src1, src2, IDecoration.TOP_LEFT) {
+				@Override
+				// Disabled by default due to https://bugs.eclipse.org/bugs/show_bug.cgi?id=97506
+				protected boolean supportsZoomLevel(int zoomLevel) {
+					return true;
+				}
+			};
 			return InternalGEFPlugin.createCursor(src, 0, 0);
 		}
 		ImageDescriptor src = InternalImages.createDescriptor(sourceName);

org.eclipse.gef/src/org/eclipse/gef/internal/InternalCursor.java

@@ -13,22 +13,10 @@
 
 package org.eclipse.gef.internal;
 
-import java.util.HashMap;
-import java.util.Map;
 import java.util.Objects;
 
-import org.eclipse.swt.SWT;
-import org.eclipse.swt.graphics.GC;
-import org.eclipse.swt.graphics.Image;
-import org.eclipse.swt.graphics.ImageData;
-import org.eclipse.swt.graphics.PaletteData;
-import org.eclipse.swt.graphics.Path;
-import org.eclipse.swt.widgets.Display;
-
 import org.eclipse.jface.resource.ImageDescriptor;
 
-import org.eclipse.draw2d.ColorConstants;
-
 /**
  * This class defines the shape of the default GEF-cursor used for the plug/tree
  * images. The cursor can't be part of the SVG itself, as it is a)
@@ -37,90 +25,26 @@
  * always has a stroke-width of 1px.
  */
 public class InternalCursor {
-	/**
-	 * Defines the shape of the cursor at 100% zoom.
-	 */
-	//@formatter:off
-	private static final float[] CURSOR_POINTS = {
-			 0f,  0f,
-			 0f, 17f,
-			 4f, 13f,
-			 7f, 19f,
-			 9f, 18f,
-			 7f, 13f,
-			 7f, 12f,
-			12f, 12f,
-			 0f,  0f
-	};
-	//@formatter:on
 	/**
 	 * Local cache to store the cursor data for each zoom level.
 	 */
-	private static final Map<Integer, ImageData> CURSOR_AT_ZOOM = new HashMap<>();
+	private static final ImageDescriptor CURSOR_AT_100_ZOOM = InternalImages.createDescriptor("icons/[email protected]"); //$NON-NLS-1$
+	private static final ImageDescriptor CURSOR_AT_150_ZOOM = InternalImages.createDescriptor("icons/[email protected]"); //$NON-NLS-1$
+	private static final ImageDescriptor CURSOR_AT_200_ZOOM = InternalImages.createDescriptor("icons/[email protected]"); //$NON-NLS-1$
 	/**
 	 * The default cursor that is constructed using {link {@link #CURSOR_POINTS}.
 	 * May be replaced with a custom cursor by calling
 	 * {@link #setCursorDescriptor(ImageDescriptor)}.
 	 */
-	private static ImageDescriptor CURRENT_CURSOR_DESCRIPTOR = ImageDescriptor
-			.createFromImageDataProvider(zoom -> CURSOR_AT_ZOOM.computeIfAbsent(zoom, InternalCursor::getCursorAtZoom));
-
-	/**
-	 * This method generates the image data for the cursor at the given zoom level.
-	 * The points defined with {@link #CURSOR_POINTS} are scaled by the given zoom
-	 * and painted onto an image.
-	 *
-	 * @param zoom The zoom level. e.g. 100, 125, 200
-	 * @return The cursor image data at the given zoom level.
-	 */
-	private static ImageData getCursorAtZoom(int zoom) {
-		float maxWidth = 0f;
-		float maxHeight = 0f;
-
-		for (int i = 0; i < CURSOR_POINTS.length; i += 2) {
-			maxWidth = Math.max(maxWidth, CURSOR_POINTS[i]);
-			maxHeight = Math.max(maxHeight, CURSOR_POINTS[i + 1]);
+	private static ImageDescriptor CURRENT_CURSOR_DESCRIPTOR = ImageDescriptor.createFromImageDataProvider(zoom -> {
+		if (zoom < 150) {
+			return CURSOR_AT_100_ZOOM.getImageData(100);
 		}
-
-		float zoomFactor = zoom / 100.0f;
-
-		int width = 1 + (int) Math.ceil(zoomFactor * maxWidth);
-		int height = 1 + (int) Math.ceil(zoomFactor * maxHeight);
-
-		//
-		Display display = Display.getDefault();
-		// Construct path
-		Path path = new Path(display);
-		for (int i = 0; i < CURSOR_POINTS.length; i += 2) {
-			float x = zoomFactor * CURSOR_POINTS[i];
-			float y = zoomFactor * CURSOR_POINTS[i + 1];
-			if (i == 0) {
-				path.moveTo(x, y);
-			} else {
-				path.lineTo(x, y);
-			}
+		if (zoom < 200) {
+			return CURSOR_AT_150_ZOOM.getImageData(100);
 		}
-		// Construct image
-		ImageData imageData = new ImageData(width, height, 32, new PaletteData(0xFF0000, 0x00FF00, 0x0000FF));
-		imageData.alphaData = new byte[width * height];
-		Image image = new Image(display, imageData);
-		GC gc = new GC(image);
-		gc.setAlpha(0);
-		gc.fillRectangle(0, 0, width, height);
-		gc.setAlpha(255);
-		gc.setAntialias(SWT.ON);
-		gc.setLineWidth(1);
-		gc.setBackground(ColorConstants.white);
-		gc.fillPath(path);
-		gc.setBackground(ColorConstants.black);
-		gc.drawPath(path);
-		gc.dispose();
-		path.dispose();
-		// Image is already scaled to expected zoom level
-		imageData = image.getImageData(100);
-		image.dispose();
-		return imageData;
-	}
+		return CURSOR_AT_200_ZOOM.getImageData(100);
+	});
 
 	/**
 	 * Returns the image descriptor for the GEF cursor. Never {@code null}.

org.eclipse.gef/src/org/eclipse/gef/internal/InternalGEFPlugin.java

@@ -127,9 +127,18 @@ public static ImageData scaledImageData(ImageDescriptor descriptor, int zoom) {
 	 */
 	public static Cursor createCursor(ImageDescriptor source, int hotspotX, int hotspotY) {
 		try {
+			ImageDataProvider provider = zoom -> {
+				if (zoom < 150) {
+					return source.getImageData(100);
+				}
+				if (zoom < 200) {
+					return source.getImageData(150);
+				}
+				return source.getImageData(200);
+			};
 			Constructor<Cursor> ctor = Cursor.class.getConstructor(Device.class, ImageDataProvider.class, int.class,
 					int.class);
-			return ctor.newInstance(null, (ImageDataProvider) source::getImageData, hotspotX, hotspotY);
+			return ctor.newInstance(null, provider, hotspotX, hotspotY);
 		} catch (NoSuchMethodException e) {
 			// SWT version < 3.131.0 (no ImageDataProvider-based constructor)
 			return new Cursor(null, source.getImageData(100), hotspotX, hotspotY); // older constructor