FontBounceTab.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.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Path;
import org.eclipse.swt.graphics.Point;

/**
 * This tab is an animated graphic. It presents the word SWT in different fonts as it bounces around the screen.
 */
public class FontBounceTab extends AnimatedGraphicsTab {

	/**
	 * Returns the name of the font using the specified index. This method takes into account the resident platform.
	 * 
	 * @param index
	 *            The index of the font to be used
	 */
	static String getPlatformFontFace(int index) {
		if (SWT.getPlatform() == "win32")
			return new String[] { "Arial", "Impact", "Times", "Verdana" }[index];
		else if (SWT.getPlatform() == "motif")
			return new String[] { "URW Chancery L", "URW Gothic L", "Times", "qub" }[index];
		else if (SWT.getPlatform() == "gtk")
			return new String[] { "URW Chancery L", "Baekmuk Batang", "Baekmuk Headline", "KacsTitleL" }[index];
		else if (SWT.getPlatform() == "carbon")
			return new String[] { "Arial", "Impact", "Times", "Verdana" }[index];
		else
			return new String[] { "Arial", "Impact", "Times", "Verdana" }[index];
	}

	int		fontFace	= 0;
	int		fontSize	= 100;
	int		fontStyle;												// represents various style attributes applicable to
	// a Font
	int		foreGrdColor, fillColor;								// font colors
	float	incX		= 10.0f;									// units by which to move the word along X axis
	float	incY		= 5.0f;									// units by which to move the word along Y axis
	String	text		= GraphicsExample.getResourceString("SWT");
	int		textWidth, textHeight;									// width and height of the word SWT

	float	x, y;

	public FontBounceTab(GraphicsExample example) {
		super(example);
	}

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

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

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

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.AnimatedGraphicsTab#next(int, int)
	 */
	public void next(int width, int height) {
		x += incX;
		y += incY;
		float random = (float) Math.random();

		// collision with right side of screen
		if (x + textWidth > width) {
			x = width - textWidth;
			incX = random * -width / 16 - 1;
			fontFace = 0;
			fontSize = 125;
			fillColor = SWT.COLOR_DARK_BLUE;
			foreGrdColor = SWT.COLOR_YELLOW;
			fontStyle = SWT.ITALIC;
		}
		// collision with left side of screen
		if (x < 0) {
			x = 0;
			incX = random * width / 16 + 1;
			fontFace = 1;
			fontSize = 80;
			fillColor = SWT.COLOR_DARK_MAGENTA;
			foreGrdColor = SWT.COLOR_CYAN;
			fontStyle = SWT.NONE;
		}
		// collision with bottom side of screen
		if (y + textHeight > height) {
			y = height - textHeight - 2;
			incY = random * -height / 16 - 1;
			fontFace = 2;
			fontSize = 100;
			fillColor = SWT.COLOR_YELLOW;
			foreGrdColor = SWT.COLOR_BLACK;
			fontStyle = SWT.BOLD;
		}
		// collision with top side of screen
		if (y < 0) {
			y = 0;
			incY = random * height / 16 + 1;
			fontFace = 3;
			fontSize = 120;
			fillColor = SWT.COLOR_GREEN;
			foreGrdColor = SWT.COLOR_GRAY;
			fontStyle = SWT.NONE;
		}
	}

	/*
	 * (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();

		Font font = new Font(device, FontBounceTab.getPlatformFontFace(fontFace), fontSize, fontStyle);
		gc.setFont(font);

		Point size = gc.stringExtent(text);
		textWidth = size.x;
		textHeight = size.y;

		Path path = new Path(device);
		path.addString(text, x, y, font);

		gc.setForeground(device.getSystemColor(foreGrdColor));
		gc.setBackground(device.getSystemColor(fillColor));

		gc.fillPath(path);
		gc.drawPath(path);
		font.dispose();
		path.dispose();
	}
}