basebmp/source/intconversion.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  19
  20 #ifndef INCLUDED_BASEBMP_SOURCE_INTCONVERSION_HXX
  21 #define INCLUDED_BASEBMP_SOURCE_INTCONVERSION_HXX
  22
  23 #include <vigra/rgbvalue.hxx>
  24 #include <functional>
  25
  26 namespace basebmp
  27 {
  28     // metafunctions to retrieve correct POD from/to basebmp::Color
  29
  30     /// type-safe conversion from RgbValue to packed int32
  31     template< class RgbVal > struct UInt32FromRgbValue
  32     {
  33         sal_uInt32 operator()( RgbVal const& c ) const
  34         {
  35             return (c[0] << 16) | (c[1] << 8) | c[2];
  36         }
  37     };
  38
  39     /// type-safe conversion from packed int32 to RgbValue
  40     template< class RgbVal > struct RgbValueFromUInt32
  41     {
  42         RgbVal operator()( sal_uInt32 c ) const
  43         {
  44             return RgbVal((c >> 16) & 0xFF,
  45                           (c >> 8) & 0xFF,
  46                           c & 0xFF);
  47         }
  48     };
  49
  50     //Current c++0x draft (apparently) has std::identity, but not operator()
  51     template<typename T> struct SGI_identity : public std::unary_function<T,T>
  52     {
  53         T& operator()(T& x) const { return x; }
  54         const T& operator()(const T& x) const { return x; }
  55     };
  56
  57     /// Get converter from given data type to sal_uInt32
  58     template< typename DataType > struct uInt32Converter
  59     {
  60         typedef SGI_identity<DataType> to;
  61         typedef SGI_identity<DataType> from;
  62     };
  63     template< unsigned int RedIndex,
  64               unsigned int GreenIndex,
  65               unsigned int BlueIndex > struct uInt32Converter<
  66                   vigra::RGBValue< sal_uInt8,
  67                                    RedIndex,
  68                                    GreenIndex,
  69                                    BlueIndex > >
  70     {
  71         typedef UInt32FromRgbValue<
  72             vigra::RGBValue< sal_uInt8,
  73                              RedIndex,
  74                              GreenIndex,
  75                              BlueIndex > >
  76             to;
  77         typedef RgbValueFromUInt32<
  78             vigra::RGBValue< sal_uInt8,
  79                              RedIndex,
  80                              GreenIndex,
  81                              BlueIndex > >
  82             from;
  83     };
  84 }
  85
  86 #endif // INCLUDED_BASEBMP_SOURCE_INTCONVERSION_HXX
  87
  88 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */