feat: Added for_each_pixel overload for any_image (#648)

Take functor by value instead of reference.
Test cases to use the same fixture as the other any_image tests.
Fixes #579

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

@@ -230,6 +230,35 @@ void fill_pixels(any_image_view<Types...> const& view, Value const& val)
     apply_operation(view, detail::fill_pixels_fn<Value>(val));
 }
 
+namespace detail {
+
+template <typename F>
+struct for_each_pixel_fn
+{
+    for_each_pixel_fn(F&& fun) : fun_(std::move(fun)) {}
+
+    template <typename View>
+    auto operator()(View const& view) -> F
+    {
+        return for_each_pixel(view, fun_);
+    }
+
+    F fun_;
+};
+
+} // namespace detail
+
+/// \defgroup ImageViewSTLAlgorithmsForEachPixel for_each_pixel
+/// \ingroup ImageViewSTLAlgorithms
+/// \brief std::for_each for any image views
+///
+/// \ingroup ImageViewSTLAlgorithmsForEachPixel
+template <typename ...Types, typename F>
+auto for_each_pixel(any_image_view<Types...> const& view, F fun) -> F
+{
+    return variant2::visit(detail::for_each_pixel_fn<F>(std::move(fun)), view);
+}
+
 }}  // namespace boost::gil
 
 #endif

test/extension/dynamic_image/Jamfile

@@ -13,3 +13,5 @@ alias headers : [ generate_self_contained_headers extension/dynamic_image ] ;
 run any_image.cpp ;
 run any_image_view.cpp ;
 run subimage_view.cpp ;
+
+build-project algorithm ;

test/extension/dynamic_image/algorithm/Jamfile

@@ -0,0 +1,11 @@
+# Boost.GIL (Generic Image Library) - tests
+#
+# Copyright (c) 2022 Marco Langer <langer.m86 at gmail dot com>
+#
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or
+# copy at http://www.boost.org/LICENSE_1_0.txt)
+
+import testing ;
+
+run for_each_pixel.cpp ;

test/extension/dynamic_image/algorithm/for_each_pixel.cpp

@@ -0,0 +1,52 @@
+//
+// Copyright 2022 Marco Langer
+//
+// Distributed under the Boost Software License, Version 1.0
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//
+#include <boost/gil/extension/dynamic_image/any_image.hpp>
+#include <boost/gil/extension/dynamic_image/algorithm.hpp>
+
+#include <boost/core/lightweight_test.hpp>
+
+#include "../test_fixture.hpp"
+#include "core/image/test_fixture.hpp"
+
+namespace gil = boost::gil;
+namespace fixture = boost::gil::test::fixture;
+
+struct accumulator
+{
+    template <typename Pixel>
+    void operator()(Pixel const& p)
+    {
+        sum += gil::at_c<0>(p);
+    }
+
+    int sum{};
+};
+
+struct test_for_each_pixel
+{
+    template <typename Image>
+    void operator()(Image const&)
+    {
+        using image_t = Image;
+        fixture::dynamic_image image(fixture::create_image<image_t>(2, 2, 128));
+        accumulator acc = gil::for_each_pixel(gil::const_view(image), accumulator());
+        BOOST_TEST_EQ(acc.sum, 2 * 2 * 128);
+    }
+
+    static void run()
+    {
+        boost::mp11::mp_for_each<fixture::image_types>(test_for_each_pixel{});
+    }
+};
+
+int main()
+{
+    test_for_each_pixel::run();
+
+    return ::boost::report_errors();
+}