| /******************************************************************************* |
| * 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.eclipse.swt.snippets; |
| |
| /* |
| * Canvas example snippet: scroll an image (flicker free, no double buffering) |
| * |
| * For a list of all SWT example snippets see |
| * http://www.eclipse.org/swt/snippets/ |
| */ |
| import org.eclipse.swt.*; |
| import org.eclipse.swt.graphics.*; |
| import org.eclipse.swt.layout.*; |
| import org.eclipse.swt.widgets.*; |
| |
| public class Snippet48 { |
| |
| public static void main (String [] args) { |
| Display display = new Display (); |
| Shell shell = new Shell (display); |
| shell.setLayout(new FillLayout()); |
| Image originalImage = null; |
| FileDialog dialog = new FileDialog (shell, SWT.OPEN); |
| dialog.setText ("Open an image file or cancel"); |
| String string = dialog.open (); |
| if (string != null) { |
| originalImage = new Image (display, string); |
| } |
| if (originalImage == null) { |
| int width = 150, height = 200; |
| originalImage = new Image (display, width, height); |
| GC gc = new GC (originalImage); |
| gc.fillRectangle (0, 0, width, height); |
| gc.drawLine (0, 0, width, height); |
| gc.drawLine (0, height, width, 0); |
| gc.drawText ("Default Image", 10, 10); |
| gc.dispose (); |
| } |
| final Image image = originalImage; |
| final Point origin = new Point (0, 0); |
| final Canvas canvas = new Canvas (shell, SWT.NO_BACKGROUND | |
| SWT.NO_REDRAW_RESIZE | SWT.V_SCROLL | SWT.H_SCROLL); |
| final ScrollBar hBar = canvas.getHorizontalBar (); |
| hBar.addListener (SWT.Selection, new Listener () { |
| public void handleEvent (Event e) { |
| int hSelection = hBar.getSelection (); |
| int destX = -hSelection - origin.x; |
| Rectangle rect = image.getBounds (); |
| canvas.scroll (destX, 0, 0, 0, rect.width, rect.height, false); |
| origin.x = -hSelection; |
| } |
| }); |
| final ScrollBar vBar = canvas.getVerticalBar (); |
| vBar.addListener (SWT.Selection, new Listener () { |
| public void handleEvent (Event e) { |
| int vSelection = vBar.getSelection (); |
| int destY = -vSelection - origin.y; |
| Rectangle rect = image.getBounds (); |
| canvas.scroll (0, destY, 0, 0, rect.width, rect.height, false); |
| origin.y = -vSelection; |
| } |
| }); |
| canvas.addListener (SWT.Resize, new Listener () { |
| public void handleEvent (Event e) { |
| Rectangle rect = image.getBounds (); |
| Rectangle client = canvas.getClientArea (); |
| hBar.setMaximum (rect.width); |
| vBar.setMaximum (rect.height); |
| hBar.setThumb (Math.min (rect.width, client.width)); |
| vBar.setThumb (Math.min (rect.height, client.height)); |
| int hPage = rect.width - client.width; |
| int vPage = rect.height - client.height; |
| int hSelection = hBar.getSelection (); |
| int vSelection = vBar.getSelection (); |
| if (hSelection >= hPage) { |
| if (hPage <= 0) hSelection = 0; |
| origin.x = -hSelection; |
| } |
| if (vSelection >= vPage) { |
| if (vPage <= 0) vSelection = 0; |
| origin.y = -vSelection; |
| } |
| canvas.redraw (); |
| } |
| }); |
| canvas.addListener (SWT.Paint, new Listener () { |
| public void handleEvent (Event e) { |
| GC gc = e.gc; |
| gc.drawImage (image, origin.x, origin.y); |
| Rectangle rect = image.getBounds (); |
| Rectangle client = canvas.getClientArea (); |
| int marginWidth = client.width - rect.width; |
| if (marginWidth > 0) { |
| gc.fillRectangle (rect.width, 0, marginWidth, client.height); |
| } |
| int marginHeight = client.height - rect.height; |
| if (marginHeight > 0) { |
| gc.fillRectangle (0, rect.height, client.width, marginHeight); |
| } |
| } |
| }); |
| shell.setSize (200, 150); |
| shell.open (); |
| while (!shell.isDisposed ()) { |
| if (!display.readAndDispatch ()) display.sleep (); |
| } |
| originalImage.dispose(); |
| display.dispose (); |
| } |
| |
| } |