SpiralTab.java

/*******************************************************************************
 * Copyright (c) 2006 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.swt.examples.graphics;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Device;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Pattern;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.Spinner;

/**
 * This tab presents a spiral consisting of the number of petals specified.
 */
public class SpiralTab extends AnimatedGraphicsTab {

	int					angle;			// angle by which to rotate the petals
	Button				colorButton;
	GraphicsBackground	foreground;
	Menu				menu;
	Spinner				petalSpinner;	// spinner to control number of petals

	public SpiralTab(GraphicsExample example) {
		super(example);
		angle = -90;
	}

	/**
	 * This method creates a spinner for specifying the number of petals. The call to the createControlPanel method in
	 * the super class create the controls that are defined in the super class.
	 * 
	 * @param parent
	 *            The parent composite
	 */
	public void createControlPanel(Composite parent) {
		super.createControlPanel(parent);

		// create spinner number of petals
		Composite comp = new Composite(parent, SWT.NONE);
		comp.setLayout(new GridLayout(2, false));

		new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("Petals")); //$NON-NLS-1$
		petalSpinner = new Spinner(comp, SWT.BORDER | SWT.WRAP);
		petalSpinner.setSelection(8);
		petalSpinner.setMinimum(3);
		petalSpinner.setMaximum(20);
		petalSpinner.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				example.redraw();
			}
		});

		// create color button
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(new GridLayout());

		ColorMenu cm = new ColorMenu();
		cm.setPatternItems(example.checkAdvancedGraphics());
		menu = cm.createMenu(parent.getParent(), new ColorListener() {
			public void setColor(GraphicsBackground gb) {
				foreground = gb;
				colorButton.setImage(gb.getThumbNail());
				example.redraw();
			}
		});

		// initialize the foreground to the 2nd item in the menu
		foreground = (GraphicsBackground) menu.getItem(1).getData();

		// color button
		colorButton = new Button(comp, SWT.PUSH);
		colorButton.setText(GraphicsExample.getResourceString("Color")); //$NON-NLS-1$
		colorButton.setImage(foreground.getThumbNail());
		colorButton.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				final Button button = (Button) event.widget;
				final Composite parent = button.getParent();
				Rectangle bounds = button.getBounds();
				Point point = parent.toDisplay(new Point(bounds.x, bounds.y));
				menu.setLocation(point.x, point.y + bounds.height);
				menu.setVisible(true);
			}
		});
	}

	public void dispose() {
		if (menu != null) {
			menu.dispose();
			menu = null;
		}
	}

	public String getCategory() {
		return GraphicsExample.getResourceString("Misc"); //$NON-NLS-1$
	}

	public String getDescription() {
		return GraphicsExample.getResourceString("SpiralDescription"); //$NON-NLS-1$
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.AnimatedGraphicsTab#getAnimationTime()
	 */
	public int getInitialAnimationTime() {
		return 150;
	}

	public String getText() {
		return GraphicsExample.getResourceString("Spiral"); //$NON-NLS-1$
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.AnimatedGraphicsTab#next(int, int)
	 */
	public void next(int width, int height) {
		if (angle == 270)
			angle = -90;
		angle += 10;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.GraphicsTab#paint(org.eclipse.swt.graphics.GC, int, int)
	 */
	public void paint(GC gc, int width, int height) {
		if (!example.checkAdvancedGraphics())
			return;
		Device device = gc.getDevice();

		// set line attributes
		gc.setLineWidth(20);
		gc.setLineCap(SWT.CAP_ROUND); // round line ends
		gc.setAntialias(SWT.ON); // smooth jagged edges

		Pattern pattern = null;
		if (foreground.getBgColor1() != null)
			gc.setForeground(foreground.getBgColor1());
		else if (foreground.getBgImage() != null) {
			pattern = new Pattern(device, foreground.getBgImage());
			gc.setForegroundPattern(pattern);
		}

		// draw petals for the spiral
		Transform transform;
		int n = petalSpinner.getSelection();
		for (int i = 0; i < n; i++) {
			transform = new Transform(device);
			transform.translate(width / 2, height / 2);
			transform.rotate(-(angle + 360 / n * i));
			gc.setTransform(transform);
			gc.drawArc(0, 0, width / 3, height / 6, 0, 180);
			transform.dispose();
		}

		if (pattern != null)
			pattern.dispose();
	}
}