| /******************************************************************************* |
| * Copyright (c) 2000, 2016 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 snippet: update a portion of a Canvas frequently |
| * |
| * 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.widgets.*; |
| |
| public class Snippet275 { |
| |
| static String value; |
| public static void main (String[] args) { |
| final int INTERVAL = 888; |
| final Display display = new Display (); |
| final Image image = new Image (display, 750, 750); |
| GC gc = new GC (image); |
| gc.setBackground (display.getSystemColor (SWT.COLOR_RED)); |
| gc.fillRectangle (image.getBounds ()); |
| gc.dispose (); |
| |
| Shell shell = new Shell (display); |
| shell.setBounds (10, 10, 790, 790); |
| final Canvas canvas = new Canvas (shell, SWT.NONE); |
| canvas.setBounds (10, 10, 750, 750); |
| canvas.addListener (SWT.Paint, event -> { |
| value = String.valueOf (System.currentTimeMillis ()); |
| event.gc.drawImage (image, 0, 0); |
| event.gc.drawString (value, 10, 10, true); |
| }); |
| display.timerExec (INTERVAL, new Runnable () { |
| @Override |
| public void run () { |
| if (canvas.isDisposed ()) return; |
| // canvas.redraw (); // <-- bad, damages more than is needed |
| GC gc = new GC (canvas); |
| Point extent = gc.stringExtent (value + '0'); |
| gc.dispose (); |
| canvas.redraw (10, 10, extent.x, extent.y, false); |
| display.timerExec (INTERVAL, this); |
| } |
| }); |
| shell.open (); |
| while (!shell.isDisposed ()){ |
| if (!display.readAndDispatch ()) display.sleep (); |
| } |
| image.dispose (); |
| display.dispose (); |
| } |
| |
| } |