1 /*
   2  * Copyright (c) 2016, 2018, 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.geom.BaseBounds;
  29 import com.sun.javafx.geom.transform.BaseTransform;
  30 import com.sun.javafx.scene.NodeHelper;
  31 import com.sun.javafx.sg.prism.NGNode;
  32 import com.sun.javafx.util.Utils;
  33 import javafx.scene.Node;
  34 import javafx.scene.canvas.Canvas;
  35 
  36 /**
  37  * Used to access internal methods of Canvas.
  38  */
  39 public class CanvasHelper extends NodeHelper {
  40     private static final CanvasHelper theInstance;
  41     private static CanvasAccessor canvasAccessor;
  42 
  43     static {
  44         theInstance = new CanvasHelper();
  45         Utils.forceInit(Canvas.class);
  46     }
  47 
  48     private static CanvasHelper getInstance() {
  49         return theInstance;
  50     }
  51 
  52     public static void initHelper(Canvas canvas) {
  53         setHelper(canvas, getInstance());
  54     }
  55 
  56     @Override
  57     protected NGNode createPeerImpl(Node node) {
  58         return canvasAccessor.doCreatePeer(node);
  59     }
  60 
  61     @Override
  62     protected void updatePeerImpl(Node node) {
  63         super.updatePeerImpl(node);
  64         canvasAccessor.doUpdatePeer(node);
  65     }
  66 
  67     @Override
  68     protected BaseBounds computeGeomBoundsImpl(Node node, BaseBounds bounds,
  69             BaseTransform tx) {
  70         return canvasAccessor.doComputeGeomBounds(node, bounds, tx);
  71     }
  72 
  73     @Override
  74     protected boolean computeContainsImpl(Node node, double localX, double localY) {
  75         return canvasAccessor.doComputeContains(node, localX, localY);
  76     }
  77 
  78     public static void setCanvasAccessor(final CanvasAccessor newAccessor) {
  79         if (canvasAccessor != null) {
  80             throw new IllegalStateException();
  81         }
  82 
  83         canvasAccessor = newAccessor;
  84     }
  85 
  86     public interface CanvasAccessor {
  87         NGNode doCreatePeer(Node node);
  88         void doUpdatePeer(Node node);
  89         BaseBounds doComputeGeomBounds(Node node, BaseBounds bounds, BaseTransform tx);
  90         boolean doComputeContains(Node node, double localX, double localY);
  91     }
  92 
  93 }