slideshow/source/inc/expressionnode.hxx

   1 /*************************************************************************
   2  *
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * Copyright 2008 by Sun Microsystems, Inc.
   6  *
   7  * OpenOffice.org - a multi-platform office productivity suite
   8  *
   9  * $RCSfile: expressionnode.hxx,v $
  10  * $Revision: 1.6 $
  11  *
  12  * This file is part of OpenOffice.org.
  13  *
  14  * OpenOffice.org is free software: you can redistribute it and/or modify
  15  * it under the terms of the GNU Lesser General Public License version 3
  16  * only, as published by the Free Software Foundation.
  17  *
  18  * OpenOffice.org is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU Lesser General Public License version 3 for more details
  22  * (a copy is included in the LICENSE file that accompanied this code).
  23  *
  24  * You should have received a copy of the GNU Lesser General Public License
  25  * version 3 along with OpenOffice.org.  If not, see
  26  * <http://www.openoffice.org/license.html>
  27  * for a copy of the LGPLv3 License.
  28  *
  29  ************************************************************************/
  30
  31 #ifndef INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX
  32 #define INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX
  33
  34 #include "animationfunction.hxx"
  35
  36
  37 /* Definition of ExpressionNode interface */
  38
  39 namespace slideshow
  40 {
  41     namespace internal
  42     {
  43         /** Refinement of AnimationFunction
  44
  45             This interface is used by the SMIL function parser, to
  46             collapse constant values into precalculated, single nodes.
  47         */
  48         class ExpressionNode : public AnimationFunction
  49         {
  50         public:
  51             /** Predicate whether this node is constant.
  52
  53                 This predicate returns true, if this node is
  54                 neither time- nor ViewInfo dependent. This allows
  55                 for certain obtimizations, i.e. not the full
  56                 expression tree needs be represented by
  57                 ExpressionNodes.
  58
  59                 @returns true, if this node is neither time- nor
  60                 ViewInfo dependent
  61             */
  62             virtual bool isConstant() const = 0;
  63         };
  64
  65         typedef ::boost::shared_ptr< ExpressionNode > ExpressionNodeSharedPtr;
  66     }
  67 }
  68
  69 #endif /* INCLUDED_SLIDESHOW_EXPRESSIONNODE_HXX */