Port TuttleOFX extension : aligned

include/boost/gil/extension/toolbox/metafunctions.hpp

@@ -8,6 +8,7 @@
 #ifndef BOOST_GIL_EXTENSION_TOOLBOX_METAFUNCTIONS_HPP
 #define BOOST_GIL_EXTENSION_TOOLBOX_METAFUNCTIONS_HPP
 
+#include <boost/gil/extension/toolbox/metafunctions/aligned.hpp>
 #include <boost/gil/extension/toolbox/metafunctions/channel_type.hpp>
 #include <boost/gil/extension/toolbox/metafunctions/channel_view.hpp>
 #include <boost/gil/extension/toolbox/metafunctions/get_num_bits.hpp>

include/boost/gil/extension/toolbox/metafunctions/aligned.hpp

@@ -0,0 +1,70 @@
+// Copyright Tom Brinkman 2008. 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)
+
+#ifndef BOOST_GIL_EXTENSION_TOOLBOX_METAFUNCTIONS_ALIGNED_HPP
+#define BOOST_GIL_EXTENSION_TOOLBOX_METAFUNCTIONS_ALIGNED_HPP
+
+#include <boost/gil.hpp>
+
+namespace boost { namespace gil {
+
+/// \brief Aligns the image view passed through struct constructor in a specific direction 
+/// inside the image view passed through the overloaded '()' operator. The direction of 
+/// alignment is specified by constructor parameters.
+template <typename View>
+struct aligned
+{
+    // Following enum variables will be used for specifying alignment of view passed through
+    // constructor with respect to the view passed through overloaded '()' operator.
+    enum
+    {
+        left = 0x1 << 0,
+        center = 0x1 << 1,
+        right = 0x1 << 2,
+        top = 0x1 << 3,
+        middle = 0x1 << 5,
+        bottom = 0x1 << 7,
+    };
+
+    View original_view;
+    int align;
+    aligned(View temp_view, int temp_align = center | middle)
+        : original_view(temp_view)
+        , align(temp_align)
+    {
+    }
+
+    void operator()(View view)
+    {
+        long int const original_view_width = original_view.width();
+        long int const original_view_height = original_view.height();
+        long int const view_width = view.width(), view_height = view.height();
+
+        // For ensuring that view passed through '()' operator has dimensions greater than or
+        // equal to the dimensions of view passed through constructor.
+        if (original_view_height > view_height || original_view_width > view_width)
+        {
+            throw std::length_error("Image view passed through overloaded '()' operator must have"
+                " dimensions greater than or equal to the dimensions of image view passed through"
+                " struct constructor");
+        }
+
+        std::ptrdiff_t x = 0;
+        if (align & center)
+            x = (view_width - original_view_width) / 2;
+        else if (align & right)
+            x = view_width - original_view_width;
+
+        std::ptrdiff_t y = 0;
+        if (align & middle)
+            y = (view_height - original_view_height) / 2;
+        else if (align & bottom)
+            y = view_height - original_view_height;
+
+        View temp_subimage_view = subimage_view(view, x, y, original_view_width, original_view_height);
+        copy_pixels(original_view, temp_subimage_view);
+    }
+}; // aligned
+}} // namespace boost::gil
+#endif

test/extension/toolbox/CMakeLists.txt

@@ -9,6 +9,7 @@
 message(STATUS "Boost.GIL: Configuring tests in test/extension/toolbox")
 
 foreach(_name
+  aligned
   channel_type
   channel_view
   color_convert_cmyka

test/extension/toolbox/Jamfile

@@ -17,6 +17,7 @@ compile is_bit_aligned.cpp ;
 compile is_homogeneous.cpp ;
 compile pixel_bit_size.cpp ;
 
+run aligned.cpp ;
 run channel_view.cpp ;
 run color_convert_cmyka.cpp ;
 run color_convert_gray.cpp ;