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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*************************************************************************
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* Copyright 2000, 2010 Oracle and/or its affiliates.
*
* OpenOffice.org - a multi-platform office productivity suite
*
* This file is part of OpenOffice.org.
*
* OpenOffice.org is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 3
* only, as published by the Free Software Foundation.
*
* OpenOffice.org 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 version 3 for more details
* (a copy is included in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with OpenOffice.org. If not, see
* <http://www.openoffice.org/license.html>
* for a copy of the LGPLv3 License.
*
************************************************************************/
#ifndef INCLUDED_BASEBMP_COLORTRAITS_HXX
#define INCLUDED_BASEBMP_COLORTRAITS_HXX
#include <basebmp/accessoradapters.hxx>
#include <basebmp/metafunctions.hxx>
#include <vigra/mathutil.hxx>
namespace basebmp
{
/** Functor template, to calculate alpha blending between two
values. Float case.
@tpl polarity
When true, 0 means fully transparent, and 1 fully opaque. And vice
versa.
*/
template< typename ValueType,
typename AlphaType,
bool polarity > struct BlendFunctor;
template< typename ValueType,
typename AlphaType > struct BlendFunctor<ValueType,AlphaType,true>
: public TernaryFunctorBase<AlphaType,ValueType,ValueType,ValueType>
{
ValueType operator()( AlphaType alpha,
ValueType v1,
ValueType v2 ) const
{
const typename vigra::NumericTraits<AlphaType>::RealPromote fAlpha(
vigra::NumericTraits<AlphaType>::toRealPromote(alpha));
return (vigra::NumericTraits<AlphaType>::one()-fAlpha)*v1 + fAlpha*v2;
}
};
template< typename ValueType,
typename AlphaType > struct BlendFunctor<ValueType,AlphaType,false>
: public TernaryFunctorBase<AlphaType,ValueType,ValueType,ValueType>
{
ValueType operator()( AlphaType alpha,
ValueType v1,
ValueType v2 ) const
{
const typename vigra::NumericTraits<AlphaType>::RealPromote fAlpha(
vigra::NumericTraits<AlphaType>::toRealPromote(alpha));
return fAlpha*v1 + (vigra::NumericTraits<AlphaType>::one()-fAlpha)*v2;
}
};
/** Functor template, to calculate alpha blending between two
values. Integer case.
@tpl polarity
When true, 0 means fully transparent, and 1 fully opaque. And vice
versa.
*/
template< typename ValueType,
typename AlphaType,
bool polarity > struct IntegerBlendFunctor;
template< typename ValueType,
typename AlphaType > struct IntegerBlendFunctor<ValueType,AlphaType,true>
: public TernaryFunctorBase<AlphaType,ValueType,ValueType,ValueType>
{
ValueType operator()( AlphaType alpha,
ValueType v1,
ValueType v2 ) const
{
return (vigra::NumericTraits<AlphaType>::toPromote(
vigra::NumericTraits<AlphaType>::max()-alpha)*v1 + alpha*v2) /
vigra::NumericTraits<AlphaType>::max();
}
};
template< typename ValueType,
typename AlphaType > struct IntegerBlendFunctor<ValueType,AlphaType,false>
: public TernaryFunctorBase<AlphaType,ValueType,ValueType,ValueType>
{
ValueType operator()( AlphaType alpha,
ValueType v1,
ValueType v2 ) const
{
return (alpha*v1 +
vigra::NumericTraits<AlphaType>::toPromote(
vigra::NumericTraits<AlphaType>::max()-alpha)*v2) /
vigra::NumericTraits<AlphaType>::max();
}
};
//-----------------------------------------------------------------------------
template< typename ColorType > struct ColorTraits
{
/// Metafunction to select blend functor from color and alpha type
template< typename AlphaType, bool polarity > struct blend_functor : public
ifScalarIntegral< AlphaType,
IntegerBlendFunctor< ColorType, AlphaType, polarity >,
BlendFunctor< ColorType, AlphaType, polarity > > {};
/// @return number of color channels
static int numChannels() { return 1; }
/// Type of a color component (i.e. the type of an individual channel)
typedef ColorType component_type;
/// Calculate normalized distance between color c1 and c2
static inline vigra::NormTraits<ColorType> distance( ColorType c1,
ColorType c2 )
{
return vigra::norm(c1 - c2);
}
static inline component_type toGreyscale( ColorType c )
{
return c;
}
static inline ColorType fromGreyscale( component_type c )
{
return c;
}
};
} // namespace basebmp
#endif /* INCLUDED_BASEBMP_COLORTRAITS_HXX */
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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