Add distance transform functionality

example/euclidean_distance_transform.cpp

@@ -0,0 +1,115 @@
+//
+// Copyright 2021 Harshit Pant <[email protected]>
+//
+// Use, modification and distribution are subject to 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/io/png.hpp>
+#include <boost/gil/image.hpp>
+#include <boost/gil/image_processing/distance_transform.hpp>
+#include <boost/gil/image_view.hpp>
+
+#include <iostream>
+
+namespace gil = boost::gil;
+
+/// calculates distance transform based on euclidean distance measurement formulae.
+
+int main(int argc, char* argv[])
+{
+    if (argc != 6)
+    {
+        std::cerr << "usage: " << argv[0]
+                  << " <input.png> <output.png>"
+                     " <distance_from> <distance_type> <mask_size>";
+        return -1;
+    }
+
+    std::string dist_from = argv[3];
+    std::string dist_type = argv[4];
+    std::string mask_size = argv[5];
+
+    gil::gray8_image_t input;
+    gil::read_image(argv[1], input, gil::png_tag{});
+    gil::gray8_image_t output(input.dimensions());
+
+    if (dist_from == "on_pixels" && dist_type == "euclidean_approximation" && mask_size == "three")
+    {
+        distance_transform(
+            view(input),
+            view(output),
+            gil::distance_from::on_pixels,
+            gil::distance_type::euclidean_approximation,
+            gil::mask_size::three);
+        gil::write_view(argv[2], view(output), gil::png_tag{});
+    }
+
+    else if (
+        dist_from == "off_pixels" && dist_type == "euclidean_approximation" && mask_size == "three")
+    {
+        distance_transform(
+            view(input),
+            view(output),
+            gil::distance_from::off_pixels,
+            gil::distance_type::euclidean_approximation,
+            gil::mask_size::three);
+        gil::write_view(argv[2], view(output), gil::png_tag{});
+    }
+
+    else if (
+        dist_from == "on_pixels" && dist_type == "euclidean_approximation" && mask_size == "five")
+    {
+        distance_transform(
+            view(input),
+            view(output),
+            gil::distance_from::on_pixels,
+            gil::distance_type::euclidean_approximation,
+            gil::mask_size::five);
+        gil::write_view(argv[2], view(output), gil::png_tag{});
+    }
+
+    else if (
+        dist_from == "off_pixels" && dist_type == "euclidean_approximation" && mask_size == "five")
+    {
+        distance_transform(
+            view(input),
+            view(output),
+            gil::distance_from::off_pixels,
+            gil::distance_type::euclidean_approximation,
+            gil::mask_size::five);
+        gil::write_view(argv[2], view(output), gil::png_tag{});
+    }
+
+    else if (
+        dist_from == "on_pixels" && dist_type == "precise_euclidean"
+        && mask_size == "not_applicable")
+    {
+        distance_transform(
+            view(input),
+            view(output),
+            gil::distance_from::on_pixels,
+            gil::distance_type::precise_euclidean,
+            gil::mask_size::not_applicable);
+        gil::write_view(argv[2], view(output), gil::png_tag{});
+    }
+
+    else if (
+        dist_from == "off_pixels" && dist_type == "precise_euclidean"
+        && mask_size == "not_applicable")
+    {
+        distance_transform(
+            view(input),
+            view(output),
+            gil::distance_from::off_pixels,
+            gil::distance_type::precise_euclidean,
+            gil::mask_size::not_applicable);
+        gil::write_view(argv[2], view(output), gil::png_tag{});
+    }
+    else
+    {
+        std::cerr << "This program fails to work with the set of arguments used. Please try again.";
+    }
+
+    return 0;
+}