1 /*
   2  * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.javafx.scene.canvas;
  27 
  28 import com.sun.javafx.scene.NodeHelper;
  29 import com.sun.javafx.sg.prism.NGNode;
  30 import com.sun.javafx.util.Utils;
  31 import javafx.scene.Node;
  32 import javafx.scene.canvas.Canvas;
  33 
  34 /**
  35  * Used to access internal methods of Canvas.
  36  */
  37 public class CanvasHelper extends NodeHelper {
  38     private static final CanvasHelper theInstance;
  39     private static CanvasAccessor canvasAccessor;
  40 
  41     static {
  42         theInstance = new CanvasHelper();
  43         Utils.forceInit(Canvas.class);
  44     }
  45 
  46     private static CanvasHelper getInstance() {
  47         return theInstance;
  48     }
  49 
  50     public static void initHelper(Canvas canvas) {
  51         setHelper(canvas, getInstance());
  52     }
  53 
  54     @Override
  55     protected NGNode createPeerImpl(Node node) {
  56         return canvasAccessor.doCreatePeer(node);
  57     }
  58 
  59     @Override
  60     protected void updatePeerImpl(Node node) {
  61         super.updatePeerImpl(node);
  62         canvasAccessor.doUpdatePeer(node);
  63     }
  64 
  65     public static void setCanvasAccessor(final CanvasAccessor newAccessor) {
  66         if (canvasAccessor != null) {
  67             throw new IllegalStateException();
  68         }
  69 
  70         canvasAccessor = newAccessor;
  71     }
  72 
  73     public interface CanvasAccessor {
  74         NGNode doCreatePeer(Node node);
  75         void doUpdatePeer(Node node);
  76     }
  77 
  78 }