slideshow/source/inc/expressionnode.hxx

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  19
  20 #ifndef INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX
  21 #define INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX
  22
  23 #include "animationfunction.hxx"
  24
  25
  26 /* Definition of ExpressionNode interface */
  27
  28 namespace slideshow
  29 {
  30     namespace internal
  31     {
  32         /** Refinement of AnimationFunction
  33
  34             This interface is used by the SMIL function parser, to
  35             collapse constant values into precalculated, single nodes.
  36         */
  37         class ExpressionNode : public AnimationFunction
  38         {
  39         public:
  40             /** Predicate whether this node is constant.
  41
  42                 This predicate returns true, if this node is
  43                 neither time- nor ViewInfo dependent. This allows
  44                 for certain obtimizations, i.e. not the full
  45                 expression tree needs be represented by
  46                 ExpressionNodes.
  47
  48                 @returns true, if this node is neither time- nor
  49                 ViewInfo dependent
  50             */
  51             virtual bool isConstant() const = 0;
  52         };
  53
  54         typedef ::boost::shared_ptr< ExpressionNode > ExpressionNodeSharedPtr;
  55     }
  56 }
  57
  58 #endif /* INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX */
  59
  60 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */