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* $RCSfile: interpolation.hxx,v $
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* $Revision: 1.5 $
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* last change: $Author: kz $ $Date: 2006-12-13 15:27:16 $
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*
* GNU Lesser General Public License Version 2.1
* =============================================
* Copyright 2005 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.
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* Lesser General Public License for more details.
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* 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,
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************************************************************************/
#ifndef _SLIDESHOW_INTERPOLATION_HXX
#define _SLIDESHOW_INTERPOLATION_HXX
#include <lerp.hxx>
namespace slideshow
{
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 */