net.sourceforge.phpeclipse.webbrowser/src/org/eclipse/webbrowser/internal/BusyIndicator.java

   1 /**
   2  * Copyright (c) 2003 IBM Corporation and others.
   3  * All rights reserved.   This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *    IBM - Initial API and implementation
  10  */
  11 package org.eclipse.webbrowser.internal;
  12
  13 import org.eclipse.swt.widgets.*;
  14 import org.eclipse.swt.events.*;
  15 import org.eclipse.swt.graphics.*;
  16 /**
  17  * An animated image to show busy status of the Web browser.
  18  */
  19 public class BusyIndicator extends Canvas {
  20         protected Image[] images;
  21         protected Image image;
  22
  23         protected Thread busyThread;
  24         protected boolean stop;
  25
  26         /**
  27          * BusyWidget constructor comment.
  28          * @param parent org.eclipse.swt.widgets.Composite
  29          * @param style int
  30          */
  31         public BusyIndicator(Composite parent, int style) {
  32                 super(parent, style);
  33
  34                 images = ImageResource.getBusyImages();
  35
  36                 addPaintListener(new PaintListener() {
  37                         public void paintControl(PaintEvent event) {
  38                                 onPaint(event);
  39                         }
  40                 });
  41
  42                 image = images[0];
  43         }
  44
  45         public Point computeSize(int wHint, int hHint, boolean changed) {
  46                 return new Point(25, 25);
  47         }
  48
  49         /**
  50          * Creates a thread to animate the image.
  51          */
  52         protected synchronized void createBusyThread() {
  53                 if (busyThread != null)
  54                         return;
  55
  56                 stop = false;
  57                 busyThread = new Thread() {
  58                         protected int count;
  59                         public void run() {
  60                                 try {
  61                                         count = 1;
  62                                         while (!stop) {
  63                                                 Display.getDefault().syncExec(new Runnable() {
  64                                                         public void run() {
  65                                                                 if (!stop) {
  66                                                                         if (count < 13)
  67                                                                                 setImage(images[count]);
  68                                                                         count++;
  69                                                                         if (count > 12)
  70                                                                                 count = 1;
  71                                                                 }
  72                                                         }
  73                                                 });
  74                                                 try {
  75                                                         sleep(125);
  76                                                 } catch (Exception e) { }
  77                                         }
  78                                         if (busyThread == null)
  79                                                 Display.getDefault().syncExec(new Thread() {
  80                                                         public void run() {
  81                                                                 setImage(images[0]);
  82                                                         }
  83                                                 });
  84                                 } catch (Exception e) {
  85                                         Trace.trace(Trace.WARNING, "Busy error", e);
  86                                 }
  87                         }
  88                 };
  89
  90                 busyThread.setPriority(Thread.NORM_PRIORITY + 2);
  91                 busyThread.setDaemon(true);
  92                 busyThread.start();
  93         }
  94
  95         public void dispose() {
  96                 stop = true;
  97                 busyThread = null;
  98                 super.dispose();
  99         }
 100
 101         /**
 102          * Return the image or <code>null</code>.
 103          */
 104         public Image getImage() {
 105                 return image;
 106         }
 107
 108         /**
 109          * Returns true if it is currently busy.
 110          *
 111          * @return boolean
 112          */
 113         public boolean isBusy() {
 114                 return (busyThread != null);
 115         }
 116
 117         /*
 118          * Process the paint event
 119          */
 120         protected void onPaint(PaintEvent event) {
 121                 Rectangle rect = getClientArea();
 122                 if (rect.width == 0 || rect.height == 0)
 123                         return;
 124
 125                 GC gc = event.gc;
 126                 if (image != null)
 127                         gc.drawImage(image, 2, 2);
 128         }
 129
 130         /**
 131          * Sets the indicators busy count up (true) or down (false) one.
 132          *
 133          * @param busy boolean
 134          */
 135         public synchronized void setBusy(boolean busy) {
 136                 if (busy) {
 137                         if (busyThread == null)
 138                                 createBusyThread();
 139                 } else {
 140                         if (busyThread != null) {
 141                                 stop = true;
 142                                 busyThread = null;
 143                         }
 144                 }
 145         }
 146
 147         /**
 148          * Set the image.
 149          * The value <code>null</code> clears it.
 150          */
 151         public void setImage(Image image) {
 152                 if (image != this.image && !isDisposed()) {
 153                         this.image = image;
 154                         redraw();
 155                 }
 156         }
 157 }