fix: Fixed custom color converter in dynamic_factory and added corres…

…ponding (#726)

include/boost/gil/extension/dynamic_image/image_view_factory.hpp

@@ -314,20 +314,12 @@ auto nth_channel_view(any_image_view<Views...> const& src, int n)
 
 namespace detail {
 
-template <typename View, typename DstP, typename CC>
-struct get_ccv_type : color_converted_view_type<View, DstP, CC> {};
-
 template <typename Views, typename DstP, typename CC>
 struct views_get_ccv_type
 {
 private:
-    // FIXME: Remove class name injection with detail:: qualification
-    // Required as workaround for MP11 issue that treats unqualified metafunction
-    // in the class definition of the same name as the specialization (Peter Dimov):
-    //    invalid template argument for template parameter 'F', expected a class template
-    template <typename T>
-    using ccvt = detail::get_ccv_type<T, DstP, CC>;
-
+   template <typename T>
+    using ccvt = typename color_converted_view_type<T, DstP, CC>::type;
 public:
     using type = mp11::mp_transform<ccvt, Views>;
 };
@@ -340,27 +332,27 @@ template <typename ...Views, typename DstP, typename CC>
 struct color_converted_view_type<any_image_view<Views...>,DstP,CC>
 {
     //using type = any_image_view<typename detail::views_get_ccv_type<Views, DstP, CC>::type>;
-    using type = detail::views_get_ccv_type<any_image_view<Views...>, DstP, CC>;
+    using type = typename detail::views_get_ccv_type<any_image_view<Views...>, DstP, CC>::type;
 };
 
 /// \ingroup ImageViewTransformationsColorConvert
 /// \brief overload of generic color_converted_view with user defined color-converter
 /// \tparam Views Models Boost.MP11-compatible list of models of ImageViewConcept
 template <typename DstP, typename ...Views, typename CC>
 inline
-auto color_converted_view(any_image_view<Views...> const& src, CC)
+auto color_converted_view(any_image_view<Views...> const& src, CC cc)
     -> typename color_converted_view_type<any_image_view<Views...>, DstP, CC>::type
 {
     using cc_view_t = typename color_converted_view_type<any_image_view<Views...>, DstP, CC>::type;
-    return variant2::visit(detail::color_converted_view_fn<DstP, cc_view_t>(), src);
+    return variant2::visit(detail::color_converted_view_fn<DstP, cc_view_t, CC>(cc), src);
 }
 
 /// \ingroup ImageViewTransformationsColorConvert
 /// \brief Returns the type of a runtime-specified view, color-converted to a given pixel type with the default coor converter
 template <typename ...Views, typename DstP>
 struct color_converted_view_type<any_image_view<Views...>,DstP>
 {
-    using type = detail::views_get_ccv_type<any_image_view<Views...>, DstP, default_color_converter>;
+    using type = typename detail::views_get_ccv_type<any_image_view<Views...>, DstP, default_color_converter>::type;
 };
 
 /// \ingroup ImageViewTransformationsColorConvert

test/extension/dynamic_image/image_view_factory.cpp

@@ -83,10 +83,77 @@ struct test_flipped_up_down_view
     }
 };
 
+template<typename V1, typename V2>
+bool equal_pixels_values(V1&& v1, 
+    V2&& v2,
+    float threshold = 1e-6f)
+{
+// convert both images to rgba32f and compare with threshold
+   return boost::variant2::visit([=](auto const& v1, auto const& v2) -> bool {
+        auto it1 = v1.begin();
+        auto it2 = v2.begin();
+        while(it1 != v1.end() && it2 != v2.end()) {
+            using pixel_t = gil::rgba32f_pixel_t;
+            static constexpr std::size_t num_channels = gil::num_channels<pixel_t>::value;
+            pixel_t p1{};
+            gil::color_convert(*it1++, p1);
+            pixel_t p2{};
+            gil::color_convert(*it2++, p2);
+            for(size_t i = 0; i < num_channels; ++i) {
+                if(std::abs(p1[i] - p2[i]) > threshold){
+                    return false;
+                }
+            }
+        }
+        return true;
+    }, 
+    std::forward<V1>(v1), 
+    std::forward<V2>(v2));
+}
+
+struct test_color_converted_view
+{
+    static void run()
+    {
+        using dynamic_image_t = gil::any_image<gil::gray8_image_t, gil::gray16_image_t>;
+        using src_image_t = gil::gray8_image_t;
+        using dst_image_t = gil::gray16_image_t;
+        using dst_pixel_t = typename dst_image_t::value_type;
+        static constexpr std::size_t num_channels = 1;
+        auto color_converter = [](auto const& src, auto& dst) { dst = 2 * src; };
+        std::array<int, 9> pixel_data =
+        {
+            0, 1, 2,
+            3, 4, 5,
+            6, 7, 8
+        };
+        std::array<int, 9> expected_pixel_data;
+        std::transform(std::begin(pixel_data), 
+            std::end(pixel_data), 
+            std::begin(expected_pixel_data), 
+            [](auto v) { return 2 * v; });
+
+        dynamic_image_t source_image =
+        fixture::generate_image<src_image_t>(
+                3, 3, generator<num_channels>{pixel_data.data()});
+
+        dynamic_image_t expected_image =
+            fixture::generate_image<dst_image_t>(
+                3, 3, generator<num_channels>{expected_pixel_data.data()});
+
+        auto result_view = gil::color_converted_view<dst_pixel_t>(gil::const_view(source_image), color_converter);
+
+        BOOST_TEST(equal_pixels_values(result_view, 
+            gil::const_view(expected_image), 
+            1e-6f)); 
+    }
+};
 
 int main()
 {
     test_flipped_up_down_view::run();
 
+    test_color_converted_view::run();
+
     return ::boost::report_errors();
 }