ImageProgressBar.java

/*******************************************************************************
 * Copyright (c) 2009 Paul VanderLei, Simon Archer, Jeff McAffer and others. All
 * rights reserved. This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License v1.0 and Eclipse
 * Distribution License v1.0 which accompanies this distribution. The Eclipse
 * Public License is available at http://www.eclipse.org/legal/epl-v10.html and
 * the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 * 
 * Contributors: Paul VanderLei, Simon Archer, Jeff McAffer - initial API and
 * implementation
 *******************************************************************************/
package org.eclipse.examples.toast.crust.widgets;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;

public class ImageProgressBar extends Canvas {

	private Image image;
	private int selection;
	private int privateStyle;
	private int minimum;
	private int maximum;
	private boolean wiggle;

	public ImageProgressBar(Composite parent, int style) {
		super(parent, checkStyle(style));
		wiggle = false;
		privateStyle = checkPrivateStyle(style);
		addDisposeListener(new DisposeListener() {

			public void widgetDisposed(DisposeEvent e) {
				ImageProgressBar.this.widgetDisposed(e);
			}

		});
		addPaintListener(new PaintListener() {

			public void paintControl(PaintEvent e) {
				ImageProgressBar.this.paintControl(e);
			}

		});
		selection = 0;
		minimum = 0;
		maximum = 100;
		String vendor = System.getProperty("java.vm.vendor");
		if ((vendor != null) & vendor.startsWith("\"Apple"))
			wiggle = true;
	}

	public void setSelection(int selection) {
		if (selection < minimum)
			this.selection = minimum;
		else if (selection > maximum)
			this.selection = maximum;
		else
			this.selection = selection;
		updateRegion();
	}

	public int getSelection() {
		return selection;
	}

	private void paintControl(PaintEvent e) {
		GC gc = e.gc;
		Rectangle size = getBounds();
		if (image != null) {
			Rectangle iSize = image.getBounds();
			int widthOffset = computeOffset(size.width, iSize.width);
			int heightOffset = computeOffset(size.height, iSize.height);
			gc.drawImage(image, widthOffset, heightOffset);
		}
	}

	private int computeOffset(int i, int j) {
		if (j >= i)
			return 0;
		else
			return (i - j) / 2;
	}

	private void widgetDisposed(DisposeEvent e) {
		Region region = getRegion();
		if (region != null)
			region.dispose();
	}

	public void setImage(Image image) {
		this.image = image;
		updateRegion();
	}

	public Image getImage() {
		return image;
	}

	private void updateRegion() {
		int style = privateStyle;
		Region region = getRegion();
		if (region != null)
			region.dispose();
		region = new Region();
		Point extents = getSize();
		Rectangle rectangle = new Rectangle(0, 0, extents.x, extents.y);
		if ((style & SWT.HORIZONTAL) != 0) {
			if ((style & SWT.LEFT_TO_RIGHT) != 0) {
				rectangle.width = (rectangle.width * (selection - minimum)) / maximum;
			} else {
				int offset = (rectangle.width * (selection - minimum)) / maximum;
				rectangle.x = rectangle.width - offset;
				rectangle.width = offset;
			}
		} else {
			if ((style & SWT.DOWN) != 0) {
				rectangle.height = (rectangle.height * (selection - minimum)) / maximum;
			} else {
				int offset = (rectangle.height * (selection - minimum)) / maximum;
				rectangle.y = offset;
				rectangle.height = offset;
			}
		}
		region.add(rectangle);
		setRegion(region);
		if (wiggle) {
			Rectangle bounds = getBounds();
			setBounds(bounds.x + 1, bounds.y + 1, bounds.width, bounds.height);
			setBounds(bounds);
		}
		redraw();
	}

	private static int checkStyle(int style) {
		// SWT.HORIZONTAL and SWT.VERTICAL cause scroll bars which we don't want
		// so eliminate them
		style |= SWT.NO_FOCUS;
		int mask = SWT.HORIZONTAL | SWT.VERTICAL | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT | SWT.UP | SWT.DOWN;
		return style & ~mask;
	}

	private int checkBits(int style, int int0, int int1) {
		int mask = int0 | int1;
		if ((style & mask) == 0)
			style |= int0;
		if ((style & int0) != 0)
			style = style & ~mask | int0;
		if ((style & int1) != 0)
			style = style & ~mask | int1;
		return style;
	}

	private int checkPrivateStyle(int style) {
		style = checkBits(style, SWT.HORIZONTAL, SWT.VERTICAL);
		if ((style & SWT.HORIZONTAL) != 0) {
			return checkBits(style, SWT.LEFT_TO_RIGHT, SWT.RIGHT_TO_LEFT);
		}
		if ((style & SWT.VERTICAL) != 0) {
			return checkBits(style, SWT.UP, SWT.DOWN);
		}
		return style;
	}

	public int getMinimum() {
		return minimum;
	}

	public void setMinimum(int minimum) {
		if (minimum < 0) {
			return;
		} else {
			this.minimum = minimum;
			updateRegion();
			return;
		}
	}

	public int getMaximum() {
		return maximum;
	}

	public void setMaximum(int maximum) {
		if ((maximum < 0) | (maximum < minimum)) {
			return;
		} else {
			this.maximum = maximum;
			updateRegion();
			return;
		}
	}

}