Source for gnu.java.awt.peer.qt.QtRepaintThread

   1: /* QtRepaintThread.java -- Repaint thread implementation
   2:    Copyright (C)  2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package gnu.java.awt.peer.qt;
  39: 
  40: /**
  41:  * This class does repainting of Component back-buffers. It is undesirable to
  42:  * do this directly from the paint callback in QtComponentPeer, because that
  43:  * is executed from the main thread. Thus, if a call is made at the same time
  44:  * which requires execution by the main thread, and this is sharing a lock with
  45:  * paint(), then a deadlock will occur, which must be avoided. In general,
  46:  * the main Qt thread should avoid calling into java code as far as possible.
  47:  *
  48:  */
  49: public class QtRepaintThread extends Thread
  50: {
  51:   static class RepaintComponent
  52:   {
  53:     public QtComponentPeer curr;
  54:     public RepaintComponent next;
  55:     public boolean paintAll;
  56:     public int x, y, w, h;
  57: 
  58:     public RepaintComponent(QtComponentPeer p)
  59:     {
  60:       curr = p;
  61:       next = null;
  62:       paintAll = true;
  63:     }
  64: 
  65:     public RepaintComponent(QtComponentPeer p, int x, int y, int w, int h)
  66:     {
  67:       this(p);
  68:       paintAll = false;
  69:       this.x = x;
  70:       this.y = y;
  71:       this.w = w;
  72:       this.h = h;
  73:     }
  74:   }
  75: 
  76:   RepaintComponent component;
  77:   boolean busy;
  78: 
  79:   public QtRepaintThread()
  80:   {
  81:     component = null;
  82:   }
  83: 
  84:   public void run()
  85:   {
  86:     while( true )
  87:       {
  88:         try
  89:           {
  90:             busy = false;
  91:             // Wait for a repaint
  92:             sleep(100);
  93:             busy = true;
  94:           }
  95:         catch (InterruptedException ie)
  96:           {
  97:             while( component != null )
  98:               {
  99:                 try
 100:                   {
 101:                     if( component.paintAll )
 102:                       {
 103:                         // update the back-buffer.
 104:                         component.curr.paintBackBuffer();
 105:                         component.curr.QtUpdate(); // trigger a native repaint event
 106:                       }
 107:                     else
 108:                       {
 109:                         component.curr.paintBackBuffer(component.x, component.y,
 110:                                                        component.w, component.h);
 111:                         component.curr.QtUpdateArea(component.x, component.y,
 112:                                                     component.w, component.h);
 113:                       }
 114:                   }
 115:                 catch (InterruptedException e)
 116:                   {
 117:                   }
 118:                 component = component.next;
 119:               }
 120:           }
 121:       }
 122:   }
 123: 
 124:   /**
 125:    * Enqueue a component for repainting.
 126:    */
 127:   public synchronized void queueComponent(QtComponentPeer p)
 128:   {
 129:     if( component == null )
 130:       component = new RepaintComponent(p);
 131:     else
 132:       {
 133:         RepaintComponent r = component;
 134:         while( r.next != null ) r = r.next;
 135:         r.next = new RepaintComponent(p);
 136:       }
 137:     interrupt();
 138:   }
 139: 
 140:   /**
 141:    * Enqueue a component for repainting.
 142:    */
 143:   public synchronized void queueComponent(QtComponentPeer p, int x, int y,
 144:                                           int w, int h)
 145:   {
 146:     if( component == null )
 147:       component = new RepaintComponent(p, x, y, w, h);
 148:     else
 149:       {
 150:         RepaintComponent r = component;
 151:         while( r.next != null ) r = r.next;
 152:         r.next = new RepaintComponent(p, x, y, w, h);
 153:       }
 154:     interrupt();
 155:   }
 156: }