bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/DragHandle.java

/*******************************************************************************
 * Copyright (c) 2005, 2019 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *     Lars Vogel <Lars.Vogel@gmail.com> - Bug 422040
 *     Alexander Fedorov <alexander.fedorov@arsysop.ru> - Bug 548799
 *******************************************************************************/
package org.eclipse.ui.internal;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;

public class DragHandle extends Composite implements PaintListener {

	Image handleImage;
	private boolean isHorizontal;

	private static int margin = 2;

	public DragHandle(Composite parent) {
		super(parent, SWT.NONE);

		addPaintListener(this);

		handleImage = new Image(parent.getDisplay(), 4, 4);
		GC context = new GC(handleImage);
		context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_BACKGROUND));
		context.drawPoint(0, 0);
		context.drawPoint(2, 0);
		context.drawPoint(3, 0);
		context.drawPoint(3, 1);
		context.drawPoint(0, 2);
		context.drawPoint(3, 2);
		context.drawPoint(0, 3);
		context.drawPoint(1, 3);
		context.drawPoint(2, 3);
		context.drawPoint(3, 3);

		context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW));
		context.drawPoint(1, 0);
		context.drawPoint(0, 1);

		context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_DARK_SHADOW));
		context.drawPoint(1, 1);

		context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_HIGHLIGHT_SHADOW));
		context.drawPoint(1, 2);
		context.drawPoint(2, 1);
		context.drawPoint(2, 2);

		context.dispose();

		setCursor(parent.getDisplay().getSystemCursor(SWT.CURSOR_SIZEALL));
	}

	@Override
	public void paintControl(PaintEvent e) {
		Point size = getSize();

		if (handleImage != null) {
			Rectangle ibounds = handleImage.getBounds();

			int x = ((size.x - 2 * margin) % ibounds.width) / 2 + margin;
			int y = ((size.y - 2 * margin) % ibounds.height) / 2 + margin;

			for (;;) {
				e.gc.drawImage(handleImage, x, y);
				if (isHorizontal) {
					x += ibounds.width;
					if (x + ibounds.width > size.x - margin) {
						break;
					}
				} else {
					y += ibounds.height;
					if (y + ibounds.height > size.y - margin) {
						break;
					}
				}
			}
		}
	}

	@Override
	public Point computeSize(int wHint, int hHint, boolean changed) {
		Point result = new Point(wHint, hHint);

		Rectangle ibounds = handleImage.getBounds();

		if (wHint == SWT.DEFAULT) {
			result.x = ibounds.width + 2 * margin;
		}

		if (hHint == SWT.DEFAULT) {
			result.y = ibounds.height + 2 * margin;
		}

		return result;
	}

	public void setHorizontal(boolean isHorizontal) {
		this.isHorizontal = isHorizontal;
	}

	@Override
	public void dispose() {
		if (isDisposed()) {
			return;
		}
		handleImage.dispose();
		super.dispose();
	}
}