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#ifndef INCLUDED_SLIDESHOW_ANIMATIONFUNCTION_HXX
#define INCLUDED_SLIDESHOW_ANIMATIONFUNCTION_HXX

#include <sal/config.h>
#include <boost/shared_ptr.hpp>


/* Definition of AnimationFunction interface */

namespace slideshow
{
    namespace internal
    {
        /** Interface describing an abstract animation function.

        	Use this interface to model time-dependent animation
        	functions of one variable.
         */
        class AnimationFunction
        {
        public:
            virtual ~AnimationFunction() {}

            /** Operator to calculate function value.

            	This method calculates the function value for the
            	given time instant t. 

                @param t
                Current time instant, must be in the range [0,1]

                @return the function value, typically in relative
                user coordinate space ([0,1] range).
             */
            virtual double operator()( double t ) const = 0;

        };

        typedef ::boost::shared_ptr< AnimationFunction > AnimationFunctionSharedPtr;

    }
}

#endif /* INCLUDED_SLIDESHOW_ANIMATIONFUNCTION_HXX */