countdowntab.java

SUN公司eclipse3.2.2经典例子

/*******************************************************************************
 * 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 presents a count down from 5 to 1, then displays SWT.
 * */
public class CountDownTab extends AnimatedGraphicsTab {

	final int startNumber = 5;			// number at which to start the countdown
	int nextNumber = startNumber;		// next number to be displayed
	int angle = -90;					// angle used to rotate the bar

	Spinner lineWidthSpinner;			// spinner for line width
	Combo aliasCombo, lineCapCombo;		// combo for alias type and line cap
	int antialias, lineCap;				// antialias and linecap values
	int[] capValues = { SWT.CAP_FLAT, SWT.CAP_SQUARE, SWT.CAP_ROUND };
	int[] aliasValues = { SWT.DEFAULT, SWT.OFF, SWT.ON };

	/**
	 * Constructor
	 * 
	 * @param example
	 *            A GraphicsExample
	 */
	public CountDownTab(GraphicsExample example) {
		super(example);
	}

	/**
	 * This method creates the controls specific to the tab. 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);

		if (nextNumber < 1)
			nextNumber = startNumber;

		// add selection listener to reset nextNumber after
		// the sequence has completed
		playItem.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				if (nextNumber < 1)
					nextNumber = startNumber;
			}
		});

		Composite comp;
		GridLayout gridLayout = new GridLayout(2, false);

		// create spinner for line width
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(gridLayout);
		new Label(comp, SWT.CENTER).setText(GraphicsExample
				.getResourceString("LineWidth")); //$NON-NLS-1$
		lineWidthSpinner = new Spinner(comp, SWT.BORDER | SWT.WRAP);
		lineWidthSpinner.setSelection(20);
		lineWidthSpinner.setMinimum(1);
		lineWidthSpinner.setMaximum(100);
		lineWidthSpinner.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				if (!pauseItem.isEnabled()) {
					example.redraw();
				}
			}
		});

		// create drop down combo for antialiasing
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(gridLayout);
		new Label(comp, SWT.CENTER).setText(GraphicsExample
				.getResourceString("Antialiasing")); //$NON-NLS-1$
		aliasCombo = new Combo(comp, SWT.DROP_DOWN);
		aliasCombo.add("DEFAULT");
		aliasCombo.add("OFF");
		aliasCombo.add("ON");
		aliasCombo.select(0);
		antialias = aliasValues[0];
		aliasCombo.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				antialias = aliasValues[aliasCombo.getSelectionIndex()];
				if (!pauseItem.isEnabled()) {
					example.redraw();
				}
			}
		});

		// create drop down combo for line cap
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(gridLayout);
		new Label(comp, SWT.CENTER).setText(GraphicsExample
				.getResourceString("LineCap")); //$NON-NLS-1$
		lineCapCombo = new Combo(comp, SWT.DROP_DOWN);
		lineCapCombo.add("FLAT");
		lineCapCombo.add("SQUARE");
		lineCapCombo.add("ROUND");
		lineCapCombo.select(0);
		lineCap = capValues[0];
		lineCapCombo.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				lineCap = capValues[lineCapCombo.getSelectionIndex()];
				if (!pauseItem.isEnabled()) {
					example.redraw();
				}
			}
		});
	}

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

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

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.AnimatedGraphicsTab#getAnimationTime()
	 */
	public int getInitialAnimationTime() {
		return 28;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.AnimatedGraphicsTab#next(int, int)
	 */
	public void next(int width, int height) {

		if (angle == 270) {
			nextNumber--;
			if (nextNumber < 1) {
				// stop animation
				setAnimation(false);
			}
			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();

		// diameter of the circle in pixels
		int diameter = ((width < height) ? width - 25 : height - 25);

		if (!getAnimation() && nextNumber == 0) {
			Font font = new Font(device, getPlatformFontFace(1), diameter/2,
					SWT.NONE);
			gc.setFont(font);

			// display "SWT"
			gc.setForeground(device.getSystemColor(SWT.COLOR_DARK_BLUE));
			gc.setTextAntialias(SWT.ON);

			// determine the dimensions of the word
			String text = GraphicsExample.getResourceString("SWT");
			Point point = gc.stringExtent(text);
			int textWidth = point.x;
			int textHeight = point.y;
			gc.drawString(text, (width-textWidth)/2,
					(height-textHeight)/2, true);
			font.dispose();

		} else {

			Font font = new Font(device, getPlatformFontFace(0),
					6*diameter/10, SWT.NONE);
			gc.setFont(font);

			// set attributes from controls
			gc.setLineWidth(lineWidthSpinner.getSelection());
			gc.setLineCap(lineCap); // round line ends
			gc.setAntialias(antialias); // smooth jagged edges
			gc.setTextAntialias(antialias); // smooth jagged edges

			// draw the circles
			Path path = new Path(device);
			path.addArc((width-diameter)/2, (height-diameter)/2,
					diameter, diameter, 0, 360);
			path.addArc((width-diameter+50)/2,
					(height-diameter+50)/2, diameter-50, diameter-50,
					0, 360);
			gc.drawPath(path);
			gc.setBackground(device.getSystemColor(SWT.COLOR_RED));
			gc.fillPath(path);
			path.dispose();

			Point point = gc.stringExtent(new Integer(nextNumber).toString());
			int textWidth = point.x;
			int textHeight = point.y;

			// draw the number
			gc.drawString(new Integer(nextNumber).toString(),
					(width-textWidth)/2, (height-textHeight)/2, true);

			// draw the rotating arm
			Transform transform = new Transform(device);
			transform.translate(width/2, height/2);
			transform.rotate(angle);
			gc.setTransform(transform);
			gc.setForeground(device.getSystemColor(SWT.COLOR_RED));
			gc.drawLine(0, 0, diameter/2, 0);
			transform.dispose();

			font.dispose();
		}
	}

	/**
	 * Returns the name of a valid font for the resident platform.
	 * 
	 * @param index
	 *            index is used to determine the appropriate font face
	 */
	static String getPlatformFontFace(int index) {
		if (SWT.getPlatform() == "win32") {
			return new String[] { "Courier", "Impact" }[index];
		} else if (SWT.getPlatform() == "motif") {
			return new String[] { "Courier", "URW Gothic L" }[index];
		} else if (SWT.getPlatform() == "gtk") {
			return new String[] { "Courier", "Baekmuk Headline" }[index];
		} else if (SWT.getPlatform() == "carbon") {
			return new String[] { "Courier", "Impact" }[index];
		} else { // photon, etc ...
			return new String[] { "Courier", "Verdana" }[index];
		}
	}
}