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#ifndef INCLUDED_SLIDESHOW_PAIRANIMATION_HXX
#define INCLUDED_SLIDESHOW_PAIRANIMATION_HXX

#include "animation.hxx"
#include <basegfx/tuple/b2dtuple.hxx>


/* Definition of PairAnimation interface */

namespace slideshow
{
    namespace internal
    {
        /** Interface defining a pair of numbers animation.

        	This interface is a specialization of the Animation
        	interface, and is used to animate attributes representable
        	by a pair of floating point values (e.g. a position or a
        	size).
         */
        class PairAnimation : public Animation
        {
        public:
            typedef ::basegfx::B2DTuple ValueType;

            /** Set the animation to the given value

                @param rValue
                Current animation value.
             */
            virtual bool operator()( const ValueType& rValue ) = 0;

            /** Request the underlying value for this animation.

            	This is necessary for pure To or By animations, as the
            	Activity cannot determine a sensible start value
            	otherwise.

                @attention Note that you are only permitted to query
                for the underlying value, if the animation has actually
                been started (via start() call).
             */
            virtual ValueType getUnderlyingValue() const = 0;
        };

        typedef ::boost::shared_ptr< PairAnimation > PairAnimationSharedPtr;

    }
}

#endif /* INCLUDED_SLIDESHOW_PAIRANIMATION_HXX */