include/basebmp/accessortraits.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  19
  20 #ifndef INCLUDED_BASEBMP_ACCESSORTRAITS_HXX
  21 #define INCLUDED_BASEBMP_ACCESSORTRAITS_HXX
  22
  23 #include <basebmp/accessorfunctors.hxx>
  24 #include <basebmp/accessoradapters.hxx>
  25 #include <basebmp/metafunctions.hxx>
  26
  27 #include <functional>
  28
  29 namespace basebmp
  30 {
  31
  32 struct FastMask;
  33 struct NoFastMask;
  34
  35 /// Metafunction to select output mask functor from iterator and mask value type
  36 template< typename T, typename M, bool polarity, typename DUMMY > struct outputMaskFunctorSelector : public
  37     ifBothScalarIntegral< T, M,
  38                           IntegerOutputMaskFunctor< T, M, polarity >,
  39                           GenericOutputMaskFunctor< T, M, polarity > >
  40 {
  41 };
  42 template< typename T, typename M, bool polarity > struct outputMaskFunctorSelector< T, M, polarity, FastMask > : public
  43     ifBothScalarIntegral< T, M,
  44                           FastIntegerOutputMaskFunctor< T, M, polarity >,
  45                           GenericOutputMaskFunctor< T, M, polarity > >
  46 {
  47 };
  48
  49 /** Metafunction providing a point of configuration for iterators
  50     capable of employing the fast output mask functor.
  51
  52     Specialize this metafunction for your case, and pass FastMask to
  53     the outputMaskFunctorSelector.
  54  */
  55 template< class Accessor,
  56           class MaskAccessor,
  57           class Iterator,
  58           class MaskIterator,
  59           bool  polarity > struct maskedAccessorSelector
  60 {
  61     typedef TernarySetterFunctionAccessorAdapter<
  62         Accessor,
  63         MaskAccessor,
  64         typename outputMaskFunctorSelector<
  65             typename Accessor::value_type,
  66             typename MaskAccessor::value_type,
  67             polarity,
  68             NoFastMask > ::type >
  69         type;
  70 };
  71
  72 //-----------------------------------------------------------------------------
  73
  74 /** Traits template for Accessor
  75
  76     Provides wrapped types for color lookup, raw pixel access, xor and
  77     mask accessors.
  78  */
  79 template< class Accessor > struct AccessorTraits
  80 {
  81     /// value type of described accessor
  82     typedef typename Accessor::value_type           value_type;
  83
  84     /// Retrieve stand-alone color lookup function for given Accessor type
  85     typedef project2nd< Accessor, value_type > color_lookup;
  86
  87     /// Retrieve raw pixel data accessor for given Accessor type
  88     typedef Accessor                                raw_accessor;
  89
  90     /// Retrieve wrapped accessor for XOR setter access
  91     typedef BinarySetterFunctionAccessorAdapter<
  92         Accessor,
  93         XorFunctor< value_type > >                  xor_accessor;
  94
  95     /** Retrieve masked accessor for given types
  96
  97         A masked accessor works like a filter, where the mask gates
  98         the accessor's setter methods (if the mask contains a 0 at a
  99         given iterator position, the original value is
 100         preserved. Otherwise, the new value gets set).
 101
 102         @attention be careful when retrieving a masked accessor for a
 103         set of types, and using it for a different one - there are
 104         partial specializations that take an optimized functor for
 105         certain mask accessors.
 106      */
 107     template< class MaskAccessor,
 108               class Iterator,
 109               class MaskIterator,
 110               bool  polarity > struct               masked_accessor :
 111         public maskedAccessorSelector< Accessor,
 112                                        MaskAccessor,
 113                                        Iterator,
 114                                        MaskIterator,
 115                                        polarity >
 116     {};
 117
 118 };
 119
 120 } // namespace basebmp
 121
 122 #endif /* INCLUDED_BASEBMP_ACCESSORTRAITS_HXX */
 123
 124 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */