/*******************************************************************************
* Copyright (c) 2000, 2004 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.occiware.clouddesigner.occi.examples.utils;
import org.eclipse.swt.SWT;
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.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.ScrollBar;
/**
* A <code>Canvas</code> showing a single centered SWT <code>Image</code>.
* If the <code>Image</code> is larger than the <code>Canvas<code>,
* <code>Scrollbars</code> will appear.
*/
//This code comes from org.eclipse.compare.internal
public class ImageCanvas extends Canvas {
private Image fImage;
/*
* Create a new ImageCanvas with the given SWT stylebits. (SWT.H_SCROLL and
* SWT.V_SCROLL are automtically added).
*/
public ImageCanvas(Composite parent, int style) {
super(parent, style | SWT.H_SCROLL | SWT.V_SCROLL);
ScrollBar sb = getHorizontalBar();
sb.setIncrement(20);
sb.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
repaint();
}
});
sb = getVerticalBar();
sb.setIncrement(20);
sb.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
repaint();
}
});
addListener(SWT.Resize, new Listener() {
public void handleEvent(Event e) {
updateScrollbars();
}
});
addListener(SWT.Paint, new Listener() {
public void handleEvent(Event event) {
paint(event.gc);
}
});
}
/*
* Set the SWT Image to use as the ImageCanvas contents.
*/
public void setImage(Image img) {
fImage = img;
if (!isDisposed()) {
getHorizontalBar().setSelection(0);
getVerticalBar().setSelection(0);
updateScrollbars();
getParent().layout();
redraw();
}
}
public void repaint() {
if (!isDisposed()) {
GC gc = new GC(this);
paint(gc);
gc.dispose();
}
}
void paint(GC gc) {
if (fImage != null) {
Rectangle bounds = fImage.getBounds();
Rectangle clientArea = getClientArea();
int x;
if (bounds.width < clientArea.width)
x = (clientArea.width - bounds.width) / 2;
else
x = -getHorizontalBar().getSelection();
int y;
if (bounds.height < clientArea.height)
y = (clientArea.height - bounds.height) / 2;
else
y = -getVerticalBar().getSelection();
gc.drawImage(fImage, x, y);
}
}
/**
* @private
*/
void updateScrollbars() {
Rectangle bounds = fImage != null ? fImage.getBounds() : new Rectangle(
0, 0, 0, 0);
Point size = getSize();
Rectangle clientArea = getClientArea();
ScrollBar horizontal = getHorizontalBar();
if (bounds.width <= clientArea.width) {
horizontal.setVisible(false);
horizontal.setSelection(0);
} else {
horizontal.setPageIncrement(clientArea.width
- horizontal.getIncrement());
int max = bounds.width + (size.x - clientArea.width);
horizontal.setMaximum(max);
horizontal.setThumb(size.x > max ? max : size.x);
horizontal.setVisible(true);
}
ScrollBar vertical = getVerticalBar();
if (bounds.height <= clientArea.height) {
vertical.setVisible(false);
vertical.setSelection(0);
} else {
vertical.setPageIncrement(clientArea.height
- vertical.getIncrement());
int max = bounds.height + (size.y - clientArea.height);
vertical.setMaximum(max);
vertical.setThumb(size.y > max ? max : size.y);
vertical.setVisible(true);
}
}
}