ceph/src/boost/libs/gil/test/core/color_base/static_transform_gray_to_rgb_fail.cpp

   1 //
   2 // Copyright 2019 Mateusz Loskot <mateusz at loskot dot net>
   3 //
   4 // Distributed under the Boost Software License, Version 1.0
   5 // See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt
   7 //
   8 #include <boost/gil/color_base_algorithm.hpp>
   9 #include <boost/gil/pixel.hpp>
  10 #include <boost/gil/typedefs.hpp>
  11
  12 #include <cassert>
  13 #include <cstdint>
  14
  15 namespace gil = boost::gil;
  16
  17 int main()
  18 {
  19     // K-element index must be less than size of channel_mapping_t sequence
  20     // of the *destination* color base.
  21
  22     // RGB (wider space) transformation to Gray (narrower space) takes only R channel value
  23     {
  24         gil::rgb8_pixel_t src{ 32, 64, 128 };
  25         gil::gray8_pixel_t dst{ 0 };
  26         gil::static_transform(src, dst, [](std::uint8_t src_channel) {
  27             return src_channel; // copy
  28             });
  29         assert(gil::at_c<0>(dst) == std::uint16_t{32});
  30     }
  31
  32     // Gray (narrower space) to RGB (wider space) transformation FAILS to compile
  33     {
  34         gil::gray8_pixel_t src{32};
  35         gil::rgb8_pixel_t dst{0, 0, 0};
  36         gil::static_transform(src, dst, [](std::uint8_t src_channel) {
  37             return src_channel; // copy
  38         });
  39     }
  40 }