1*b1cdbd2cSJim Jagielski /**************************************************************
2*b1cdbd2cSJim Jagielski  *
3*b1cdbd2cSJim Jagielski  * Licensed to the Apache Software Foundation (ASF) under one
4*b1cdbd2cSJim Jagielski  * or more contributor license agreements.  See the NOTICE file
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7*b1cdbd2cSJim Jagielski  * to you under the Apache License, Version 2.0 (the
8*b1cdbd2cSJim Jagielski  * "License"); you may not use this file except in compliance
9*b1cdbd2cSJim Jagielski  * with the License.  You may obtain a copy of the License at
10*b1cdbd2cSJim Jagielski  *
11*b1cdbd2cSJim Jagielski  *   http://www.apache.org/licenses/LICENSE-2.0
12*b1cdbd2cSJim Jagielski  *
13*b1cdbd2cSJim Jagielski  * Unless required by applicable law or agreed to in writing,
14*b1cdbd2cSJim Jagielski  * software distributed under the License is distributed on an
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18*b1cdbd2cSJim Jagielski  * under the License.
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20*b1cdbd2cSJim Jagielski  *************************************************************/
21*b1cdbd2cSJim Jagielski 
22*b1cdbd2cSJim Jagielski 
23*b1cdbd2cSJim Jagielski 
24*b1cdbd2cSJim Jagielski #ifndef INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX
25*b1cdbd2cSJim Jagielski #define INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX
26*b1cdbd2cSJim Jagielski 
27*b1cdbd2cSJim Jagielski #include "animationfunction.hxx"
28*b1cdbd2cSJim Jagielski 
29*b1cdbd2cSJim Jagielski 
30*b1cdbd2cSJim Jagielski /* Definition of ExpressionNode interface */
31*b1cdbd2cSJim Jagielski 
32*b1cdbd2cSJim Jagielski namespace slideshow
33*b1cdbd2cSJim Jagielski {
34*b1cdbd2cSJim Jagielski     namespace internal
35*b1cdbd2cSJim Jagielski     {
36*b1cdbd2cSJim Jagielski         /** Refinement of AnimationFunction
37*b1cdbd2cSJim Jagielski 
38*b1cdbd2cSJim Jagielski 	        This interface is used by the SMIL function parser, to
39*b1cdbd2cSJim Jagielski 	        collapse constant values into precalculated, single nodes.
40*b1cdbd2cSJim Jagielski         */
41*b1cdbd2cSJim Jagielski         class ExpressionNode : public AnimationFunction
42*b1cdbd2cSJim Jagielski         {
43*b1cdbd2cSJim Jagielski         public:
44*b1cdbd2cSJim Jagielski             /** Predicate whether this node is constant.
45*b1cdbd2cSJim Jagielski 
46*b1cdbd2cSJim Jagielski         	    This predicate returns true, if this node is
47*b1cdbd2cSJim Jagielski                 neither time- nor ViewInfo dependent. This allows
48*b1cdbd2cSJim Jagielski                 for certain obtimizations, i.e. not the full
49*b1cdbd2cSJim Jagielski                 expression tree needs be represented by
50*b1cdbd2cSJim Jagielski                 ExpressionNodes.
51*b1cdbd2cSJim Jagielski 
52*b1cdbd2cSJim Jagielski                 @returns true, if this node is neither time- nor
53*b1cdbd2cSJim Jagielski                 ViewInfo dependent
54*b1cdbd2cSJim Jagielski             */
55*b1cdbd2cSJim Jagielski             virtual bool isConstant() const = 0;
56*b1cdbd2cSJim Jagielski         };
57*b1cdbd2cSJim Jagielski 
58*b1cdbd2cSJim Jagielski         typedef ::boost::shared_ptr< ExpressionNode > ExpressionNodeSharedPtr;
59*b1cdbd2cSJim Jagielski     }
60*b1cdbd2cSJim Jagielski }
61*b1cdbd2cSJim Jagielski 
62*b1cdbd2cSJim Jagielski #endif /* INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX */
63