Attachment 184385 Details for Bug 331711 – snippet that creates a resize tracker on a tree, and lags in resize event

snippet that creates a resize tracker on a tree, and lags in resize event

TrackerSnippet.java (text/x-java-source), 2.69 KB, created by Andrei Diaconu

on 2010-12-02 14:30:36 EST

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Filename:

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Creator: Andrei Diaconu

Created: 2010-12-02 14:30:36 EST

Size: 2.69 KB

patch

obsolete

>import java.util.ArrayList;
>import java.util.List;
>
>import org.eclipse.swt.SWT;
>import org.eclipse.swt.graphics.Point;
>import org.eclipse.swt.graphics.Rectangle;
>import org.eclipse.swt.layout.FillLayout;
>import org.eclipse.swt.widgets.*;
>
>public class TrackerSnippet {
>
>	public static void main(String[] args) {
>		final Display display = new Display();
>		final Shell shell = new Shell(display);
>		shell.setLayout(new FillLayout());
>
>		final Tree tree = new Tree(shell, SWT.BORDER | SWT.MULTI);
>		for (int i = 0; i < 10000; i++) {
>			final TreeItem item = new TreeItem(tree, SWT.NONE);
>			item.setText("Item - " + i);
>		}
>
>		tree.addListener(SWT.MouseDown, new Listener() {
>			@Override
>			public void handleEvent(Event e) {
>				createTracker(e, tree);
>			}
>		});
>		shell.open();
>		while (!shell.isDisposed()) {
>			if (!display.readAndDispatch()) {
>				display.sleep();
>			}
>		}
>		display.dispose();
>	}
>
>	private static void createTracker(Event e, final Tree tree) {
>		final Tracker tracker = new Tracker(tree, SWT.RESIZE);
>		tracker.setRectangles(new Rectangle[]{new Rectangle(e.x, e.y, 0, 0),});
>
>		tracker.addListener(SWT.Resize, new Listener() {
>			@Override
>			public void handleEvent(Event event) {
>				final Rectangle[] rectangles = tracker.getRectangles();
>				final Rectangle bounds = rectangles[0];
>
>				final TreeItem[] items = getItems(tree, bounds);
>				select(tree, items);
>
>				final TreeItem item = tree.getItem(new Point(event.x, event.y));
>				if (item != null) {
>					tree.setSelection(item);
>				}
>			}
>		});
>
>		tracker.open();
>	}
>
>	/**
>	 * Returns the items that overlap at least partially with the given rectangle.
>	 */
>	private static TreeItem[] getItems(Tree tree, Rectangle rectangle) {
>		final TreeItem topItem = tree.getTopItem();
>		final int topItemIndex = tree.indexOf(topItem);
>		final int itemsCount = tree.getItemCount();
>
>		final List<TreeItem> itemsToSelect = new ArrayList<TreeItem>();
>		for (int i = topItemIndex; i < itemsCount; i++) {
>			final TreeItem item = tree.getItem(i);
>			final Rectangle bounds = item.getBounds();
>			if (bounds.intersects(rectangle)) {
>				itemsToSelect.add(item);
>			} else {
>				if (isBelow(bounds, rectangle)) {
>					break;
>				}
>			}
>		}
>		return itemsToSelect.toArray(new TreeItem[itemsToSelect.size()]);
>	}
>
>	private static boolean isBelow(Rectangle rectangle1, Rectangle rectangle2) {
>		return rectangle1.y > rectangle2.y + rectangle2.height;
>	}
>
>	private static void select(Tree tree, TreeItem[] items) {
>		tree.setSelection(items);
>		final Event e = new Event();
>		e.widget = tree;
>		e.display = tree.getDisplay();
>		e.type = SWT.Selection;
>		tree.notifyListeners(SWT.Selection, e);
>	}
>}

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Attachments on bug 331711: 184385 | 280009