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/*************************************************************************
 *
 *  $RCSfile: interpolation.hxx,v $
 *
 *  $Revision: 1.2 $
 *
 *  last change: $Author: kz $ $Date: 2005-01-21 16:59:59 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
 *
 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (the "License"); You may not use this file
 *  except in compliance with the License. You may obtain a copy of the
 *  License at http://www.openoffice.org/license.html.
 *
 *  Software provided under this License is provided on an "AS IS" basis,
 *  WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
 *  WITHOUT LIMITATION, WARRANTIES THAT THE SOFTWARE IS FREE OF DEFECTS,
 *  MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE, OR NON-INFRINGING.
 *  See the License for the specific provisions governing your rights and
 *  obligations concerning the Software.
 *
 *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
 *
 *  Copyright: 2000 by Sun Microsystems, Inc.
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): _______________________________________
 *
 *
 ************************************************************************/

#ifndef _SLIDESHOW_INTERPOLATION_HXX
#define _SLIDESHOW_INTERPOLATION_HXX

#include <lerp.hxx>

namespace presentation
{
    namespace internal
    {
        // Interpolator specializations
        // ============================

        // NOTE: generic lerp is included from lerp.hxx. Following
        // are some specializations for various
        // not-straight-forward-interpolatable types

        /// Specialization for RGBColor, to employ color-specific interpolator
        template<> RGBColor lerp< RGBColor >( const RGBColor&   rFrom,
                                              const RGBColor&   rTo,
                                              double            t          )
        {
            return interpolate( rFrom, rTo, t );
        }

        /// Specialization also for sal_Int16, although this code should not be called
        template<> sal_Int16 lerp< sal_Int16 >( const sal_Int16&,
                                                const sal_Int16&    rTo,
                                                double                     )
        {
            OSL_ENSURE( false,
                        "lerp<sal_Int16> called" );
            return rTo;
        }

        /// Specialization also for string, although this code should not be called
        template<> ::rtl::OUString lerp< ::rtl::OUString >( const ::rtl::OUString&,
                                                            const ::rtl::OUString&  rTo,
                                                            double                       )
        {
            OSL_ENSURE( false,
                        "lerp<::rtl::OUString> called" );
            return rTo;
        }

        /// Specialization also for bool, although this code should not be called
        template<> bool lerp< bool >( const bool&,
                                      const bool&   rTo,
                                      double             )
        {
            OSL_ENSURE( false,
                        "lerp<bool> called" );
            return rTo;
        }

        template< typename ValueType > struct Interpolator
        {
            ValueType operator()( const ValueType&  rFrom,
                                  const ValueType&  rTo,
                                  double            t ) const
            {
                return lerp( rFrom, rTo, t );
            }
        };

        /// Specialization for HSLColor, to employ color-specific interpolator
        template<> struct Interpolator< HSLColor >
        {
            Interpolator( bool bCCW ) :
                mbCCW( bCCW )
            {
            }

            HSLColor operator()( const HSLColor&    rFrom,
                                 const HSLColor&    rTo,
                                 double             t ) const
            {
                return interpolate( rFrom, rTo, t, mbCCW );
            }

        private:
            /// When true: interpolate counter-clockwise
            const bool mbCCW;
        };


        /** Generic linear interpolator

            @tpl ValueType
            Must have operator+ and operator* defined, and should
            have value semantics.

            @param rInterpolator
            Interpolator to use for lerp

            @param nFrame
            Must be in the [0,nTotalFrames) range

            @param nTotalFrames
            Total number of frames. Should be greater than zero.
        */
        template< typename ValueType > ValueType lerp( const Interpolator< ValueType >& rInterpolator,
                                                       const ValueType&                 rFrom,
                                                       const ValueType&                 rTo,
                                                       sal_uInt32                       nFrame,
                                                       ::std::size_t                    nTotalFrames )
        {
            // TODO(P1): There's a nice HAKMEM trick for that
            // nTotalFrames > 1 condition below

            // for 1 and 0 frame animations, always take end value
            const double nFraction( nTotalFrames > 1 ? (double)nFrame/(nTotalFrames-1) : 1.0 );

            return rInterpolator( rFrom, rTo, nFraction );
        }

        /// Specialization for non-interpolatable constants/enums
        template<> sal_Int16 lerp< sal_Int16 >( const Interpolator< sal_Int16 >&    rInterpolator,
                                                const sal_Int16&                    rFrom,
                                                const sal_Int16&                    rTo,
                                                sal_uInt32                          nFrame,
                                                ::std::size_t                       nTotalFrames )
        {
            // until one half of the total frames are over, take from value.
            // after that, take to value.
            // For nFrames not divisable by 2, we prefer to over from, which
            // also neatly yields to for 1 frame activities
            return nFrame < nTotalFrames/2 ? rFrom : rTo;
        }

        /// Specialization for non-interpolatable strings
        template<> ::rtl::OUString lerp< ::rtl::OUString >( const Interpolator< ::rtl::OUString >&  rInterpolator,
                                                            const ::rtl::OUString&                  rFrom,
                                                            const ::rtl::OUString&                  rTo,
                                                            sal_uInt32                              nFrame,
                                                            ::std::size_t                           nTotalFrames )
        {
            // until one half of the total frames are over, take from value.
            // after that, take to value.
            // For nFrames not divisable by 2, we prefer to over from, which
            // also neatly yields to for 1 frame activities
            return nFrame < nTotalFrames/2 ? rFrom : rTo;
        }

        /// Specialization for non-interpolatable bools
        template<> bool lerp< bool >( const Interpolator< bool >&   rInterpolator,
                                      const bool&                   bFrom,
                                      const bool&                   bTo,
                                      sal_uInt32                    nFrame,
                                      ::std::size_t                 nTotalFrames )
        {
            // until one half of the total frames are over, take from value.
            // after that, take to value.
            // For nFrames not divisable by 2, we prefer to over from, which
            // also neatly yields to for 1 frame activities
            return nFrame < nTotalFrames/2 ? bFrom : bTo;
        }
    }
}

#endif /* _SLIDESHOW_INTERPOLATION_HXX */