examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/graphics/TextAntialiasTab.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.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * This tab demonstrates antialiasing for text. Antialiasing is used for
 * smoothing jagged edges in graphics. This tab allows the user to see the
 * effects of different antialiasing values.
 */
public class TextAntialiasTab extends GraphicsTab {

	Combo aliasCombo;
	static int[] aliasValues = { SWT.OFF, SWT.DEFAULT, SWT.ON };
	
	Button colorButton;
	Menu menu;
	GraphicsBackground textColor;
	String text = GraphicsExample.getResourceString("SWT");

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

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

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

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

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

public void createControlPanel(Composite parent) {

	Composite comp;
	
	// create drop down combo for antialiasing
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(new GridLayout(2, false));
	new Label(comp, SWT.CENTER).setText(GraphicsExample
			.getResourceString("Antialiasing")); //$NON-NLS-1$
	aliasCombo = new Combo(comp, SWT.DROP_DOWN);
	aliasCombo.add("OFF");
	aliasCombo.add("DEFAULT");
	aliasCombo.add("ON");
	aliasCombo.select(0);
	aliasCombo.addListener(SWT.Selection, new Listener() {
		public void handleEvent(Event event) {
				example.redraw();
		}
	});
		
	ColorMenu cm = new ColorMenu();
	cm.setColorItems(true);
	menu = cm.createMenu(parent.getParent(), new ColorListener() {
		public void setColor(GraphicsBackground gb) {
			textColor = gb;
			colorButton.setImage(gb.getThumbNail());
			example.redraw();
		}
	});
	
	// create color button
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(new GridLayout());
	
	// initialize the color to black
	textColor = (GraphicsBackground)menu.getItem(1).getData();
	
	colorButton = new Button(comp, SWT.PUSH);
	colorButton.setText(GraphicsExample.getResourceString("Color")); //$NON-NLS-1$
	colorButton.setImage(textColor.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);
		}
	});
}

/* (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();
	
	if (textColor != null && textColor.getBgColor1() != null)
		gc.setForeground(textColor.getBgColor1());

	gc.setTextAntialias(aliasValues[aliasCombo.getSelectionIndex()]);

	// column 1, row 1
	Font font = new Font(device, getPlatformFontFace(0), 100, SWT.NORMAL);
	gc.setFont(font);
	Point size = gc.stringExtent(text);
	gc.drawString(text, width/4 - size.x/2, height/4 - size.y/2, true);
	font.dispose();
	
	// column 1, row 2
	font = new Font(device, getPlatformFontFace(1), 100, SWT.NORMAL);
	gc.setFont(font);
	size = gc.stringExtent(text);
	gc.drawString(text, width/4 - size.x/2, 3*height/4 - size.y/2, true);
	font.dispose();
	
	// column 2, row 1
	font = new Font(device, getPlatformFontFace(2), 50, SWT.NORMAL);
	gc.setFont(font);
	size = gc.stringExtent(text);
	gc.drawString(text, (width-size.x)/2, 0, true);
	font.dispose();
	
	// column 2, row 2
	font = new Font(device, getPlatformFontFace(3), 100, SWT.ITALIC);
	gc.setFont(font);
	size = gc.stringExtent(text);
	gc.drawString(text, (width-size.x)/2, (height-size.y)/2, true);
	font.dispose();
	
	// column 2, row 3
	font = new Font(device, getPlatformFontFace(4), 50, SWT.NORMAL);
	gc.setFont(font);
	size = gc.stringExtent(text);
	gc.drawString(text, (width-size.x)/2, height-size.y, true);
	font.dispose();
	
	// column 3, row 1
	font = new Font(device, getPlatformFontFace(5), 100, SWT.NORMAL);
	gc.setFont(font);
	size = gc.stringExtent(text);
	gc.drawString(text, 3*width/4 - size.x/2, height/4 - size.y/2, true);
	font.dispose();
	
	// column 3, row 2
	font = new Font(device, getPlatformFontFace(6), 100, SWT.NORMAL);
	gc.setFont(font);
	size = gc.stringExtent(text);
	gc.drawString(text, 3*width/4 - size.x/2, 3*height/4 - size.y/2, true);
	font.dispose();
}

/**
 * Returns the name of a valid font for the host platform.
 * 
 * @param index
 *            index is used to determine the appropriate font face
 */
static String getPlatformFontFace(int index) {
	if(SWT.getPlatform() == "win32" || SWT.getPlatform() == "wpf") {
		return new String [] {"Bookman Old Style", "Century Gothic", "Comic Sans MS", "Impact", "Garamond", "Lucida Console", "Monotype Corsiva"} [index];	
	} else if (SWT.getPlatform() == "motif") {
		return new String [] {"urw palladio l", "Courier", "qub", "URW Gothic L", "Times", "Lucida", "URW ChanceryL"} [index];
	} else if (SWT.getPlatform() == "gtk") {
		return new String [] {"Luxi Mono", "KacstTitleL", "Baekmuk Batang", "Baekmuk Headline", "KacstFarsi", "Baekmuk Gulim", "URW Chancery L"} [index];
	} else if (SWT.getPlatform() == "carbon") {
		return new String [] {"Apple Chancery", "Brush Script MT", "Comic Sans MS", "Impact", "Herculanum", "Lucida Grande", "Papyrus"} [index];
	} else { // photon, etc ...
		return new String [] {"Courier", "Verdana", "Verdana", "Verdana", "Verdana", "Verdana", "Verdana"} [index];
	}
}
}