include/basebmp/pixelformatadapters.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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   9  * This file incorporates work covered by the following license notice:
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  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_BASEBMP_PIXELFORMATADAPTERS_HXX
  21 #define INCLUDED_BASEBMP_PIXELFORMATADAPTERS_HXX
  22
  23 #include <basebmp/accessortraits.hxx>
  24 #include <basebmp/accessoradapters.hxx>
  25
  26 #include <vigra/metaprogramming.hxx>
  27
  28 namespace basebmp
  29 {
  30
  31 // convenience functionality, providing everything necessary for a new
  32 // pixel format. simply plug in two conversion functors from/to a
  33 // common color format.
  34
  35 /** Accessor selection metafunction, used to wrap a given accessor
  36     with one converting between the pixel and color types
  37
  38     Use the nested template's typedef type, to retrieve an
  39     AccessorAdapter which operates on a pixel value accessor, and
  40     provides color values to the outside.
  41
  42     Nested like this, to avoid template template parameters at other
  43     places: an instantiated version of AccessorSelector can be passed
  44     to other templates, which in turn can invoke the nested meta
  45     function.
  46  */
  47 template< typename Getter,
  48           typename Setter > struct AccessorSelector
  49 {
  50     template< typename Accessor > struct wrap_accessor
  51     {
  52         typedef UnaryFunctionAccessorAdapter< Accessor,
  53                                               Getter,
  54                                               Setter > type;
  55     };
  56 };
  57
  58 //-----------------------------------------------------------------------------
  59
  60 /** Convert color value to pixel data type
  61  */
  62 template< class Accessor, typename DataType > struct ColorConvert
  63 {
  64     DataType operator()( const Accessor&               acc,
  65                          typename Accessor::value_type v ) const
  66     {
  67         return acc.setter(v);
  68     }
  69 };
  70
  71 //-----------------------------------------------------------------------------
  72
  73 /** Macro generates partial specialization for color-conversion
  74     UnaryFunctionAccessorAdapter, and the given getter/setter functors
  75  */
  76 #define BASEBMP_SPECIALIZE_ACCESSORTRAITS(Getter,Setter)          \
  77 template< class Accessor > struct AccessorTraits<                 \
  78     UnaryFunctionAccessorAdapter< Accessor,                       \
  79                                   Getter,                         \
  80                                   Setter > >                      \
  81 {                                                                 \
  82     typedef typename Accessor::value_type          data_type;     \
  83     typedef UnaryFunctionAccessorAdapter<                         \
  84         Accessor,                                                 \
  85         Getter,                                                   \
  86         Setter >                                   accessor_type; \
  87     typedef typename accessor_type::value_type     value_type;    \
  88     typedef ColorConvert< accessor_type,                          \
  89                           data_type >              color_lookup;  \
  90     typedef Accessor                               raw_accessor;  \
  91     typedef vigra::VigraFalseType                  xor_accessor;  \
  92     template< class MaskAccessor,                                 \
  93               class Iterator,                                     \
  94               class MaskIterator > struct          masked_accessor\
  95     { typedef vigra::VigraFalseType type; };                      \
  96 }
  97
  98 } // namespace basebmp
  99
 100 #endif /* INCLUDED_BASEBMP_PIXELFORMATADAPTERS_HXX */
 101
 102 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */