bundles/org.eclipse.ui.forms/src/org/eclipse/ui/forms/widgets/TreeNode.java

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.forms.widgets;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.Composite;
/**
 * A custom selectable control that can be used to control areas that can be
 * expanded or collapsed. The control control can be toggled between selected
 * and deselected state with a mouse or by pressing 'Enter' while the control
 * has focus.
 * <p>
 * The control is rendered as box with a '+' or '-' sign, depending on the
 * expansion state. Focus indication is rendered around the box when the
 * control has keyboard focus.
 * 
 * @see Twistie
 * @since 3.0
 */
public class TreeNode extends ToggleHyperlink {
	/**
	 * Creates a control in a provided composite.
	 * 
	 * @param parent
	 *            the parent
	 * @param style
	 *            the style
	 */
	public TreeNode(Composite parent, int style) {
		super(parent, style);
		innerWidth = 10;
		innerHeight = 10;
	}
	protected void paint(PaintEvent e) {
		paintHyperlink(e.gc);
	}
	protected void paintHyperlink(GC gc) {
		Rectangle box = getBoxBounds(gc);
		gc.setForeground(getDisplay().getSystemColor(
				SWT.COLOR_WIDGET_NORMAL_SHADOW));
		gc.drawRectangle(box);
		gc.setForeground(getForeground());
		gc.drawLine(box.x + 2, box.y + 4, box.x + 6, box.y + 4);
		if (!isExpanded()) {
			gc.drawLine(box.x + 4, box.y + 2, box.x + 4, box.y + 6);
		}
		if (getSelection()) {
			gc.setForeground(getForeground());
			gc.drawFocus(box.x - 1, box.y - 1, box.width + 3, box.height + 3);
		}
	}
	private Rectangle getBoxBounds(GC gc) {
		int x = 1;
		int y = 0;
		gc.setFont(getFont());
		//int height = gc.getFontMetrics().getHeight();
		//y = height / 2 - 4;
		//y = Math.max(y, 0);
		y = 2;
		return new Rectangle(x, y, 8, 8);
	}
}