include/basebmp/colorblendaccessoradapter.hxx

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  19
  20 #ifndef INCLUDED_BASEBMP_COLORBLENDACCESSORADAPTER_HXX
  21 #define INCLUDED_BASEBMP_COLORBLENDACCESSORADAPTER_HXX
  22
  23 #include <basebmp/colortraits.hxx>
  24
  25 namespace basebmp
  26 {
  27
  28 /** Accessor adapter that blends input value against fixed color value
  29
  30     Used to blend an alpha mask 'through' a fixed color value into the
  31     destination.
  32
  33     The getter functors return a constant value (usually the zero of
  34     the value type, this preserves the original destination content
  35     when blitting through a mask) - there really isn't no other
  36     sensible default behaviour for these methods.
  37  */
  38 template< class    WrappedAccessor,
  39           typename AlphaType,
  40           bool     polarity > class ConstantColorBlendSetterAccessorAdapter
  41 {
  42 public:
  43     typedef AlphaType                            alpha_type;
  44     typedef AlphaType                            value_type;
  45     typedef typename WrappedAccessor::value_type color_type;
  46
  47 private:
  48     typename ColorTraits< color_type >::
  49              template blend_functor<alpha_type,polarity>::type   maFunctor;
  50     WrappedAccessor                                              maWrappee;
  51     color_type                                                   maBlendColor;
  52     value_type                                                   maGetterValue;
  53
  54 public:
  55     ConstantColorBlendSetterAccessorAdapter() :
  56         maFunctor(),
  57         maWrappee(),
  58         maBlendColor(),
  59         maGetterValue()
  60     {}
  61
  62     template< class T > explicit ConstantColorBlendSetterAccessorAdapter( T acc ) :
  63         maFunctor(),
  64         maWrappee(acc),
  65         maBlendColor(),
  66         maGetterValue()
  67     {}
  68
  69     template< class T > ConstantColorBlendSetterAccessorAdapter( T          acc,
  70                                                                  color_type col ) :
  71         maFunctor(),
  72         maWrappee(acc),
  73         maBlendColor(col),
  74         maGetterValue()
  75     {}
  76
  77     template< class T > ConstantColorBlendSetterAccessorAdapter( T          acc,
  78                                                                  color_type col,
  79                                                                  value_type val ) :
  80         maFunctor(),
  81         maWrappee(acc),
  82         maBlendColor(col),
  83         maGetterValue(val)
  84     {}
  85
  86     // -------------------------------------------------------
  87
  88     void        setColor( color_type col ) { maBlendColor=col; }
  89     color_type  getColor() { return maBlendColor; }
  90     void        setGetterValue( value_type val ) { maGetterValue=val; }
  91     value_type  getGetterValue() { return maGetterValue; }
  92
  93     // -------------------------------------------------------
  94
  95     WrappedAccessor const& getWrappedAccessor() const { return maWrappee; }
  96     WrappedAccessor&       getWrappedAccessor() { return maWrappee; }
  97
  98     // -------------------------------------------------------
  99
 100     /// @return constant value, regardless of iterator content
 101     template< typename IteratorType > value_type operator()(SAL_UNUSED_PARAMETER IteratorType const& ) const
 102     {
 103         return maGetterValue;
 104     }
 105     /// @return constant value, regardless of iterator content
 106     template< typename IteratorType, class Difference >
 107     value_type operator()(SAL_UNUSED_PARAMETER IteratorType const& , SAL_UNUSED_PARAMETER Difference const& ) const
 108     {
 109         return maGetterValue;
 110     }
 111
 112     // -------------------------------------------------------
 113
 114     template< typename V, typename IteratorType >
 115     void set(V const& value, IteratorType const& i) const
 116     {
 117         maWrappee.set(
 118             maFunctor(
 119                 vigra::detail::RequiresExplicitCast<alpha_type>::cast(value),
 120                 maWrappee(i),
 121                 maBlendColor),
 122             i );
 123     }
 124
 125     template< typename V, typename IteratorType, class Difference >
 126     void set(V const& value, IteratorType const& i, Difference const& diff) const
 127     {
 128         maWrappee.set(
 129             maFunctor(
 130                 vigra::detail::RequiresExplicitCast<alpha_type>::cast(value),
 131                 maWrappee(i,diff),
 132                 maBlendColor),
 133             i,
 134             diff );
 135     }
 136 };
 137
 138 } // namespace basebmp
 139
 140 #endif /* INCLUDED_BASEBMP_COLORBLENDACCESSORADAPTER_HXX */
 141
 142 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */