1 files changed, 49 insertions, 0 deletions
diff --git a/src/boost/libs/gil/example/histogram.cpp b/src/boost/libs/gil/example/histogram.cpp
new file mode 100644
index 00000000..b1b48964
--- /dev/null
+++ b/src/boost/libs/gil/example/histogram.cpp
@@ -0,0 +1,49 @@
+//
+// Copyright 2005-2007 Adobe Systems Incorporated
+//
+// 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.hpp>
+#include <boost/gil/extension/io/jpeg.hpp>
+
+#include <algorithm>
+#include <fstream>
+
+// Example file to demonstrate a way to compute histogram
+
+using namespace boost::gil;
+
+template <typename GrayView, typename R>
+void gray_image_hist(GrayView const& img_view, R& hist)
+{
+    for (auto it = img_view.begin(); it != img_view.end(); ++it)
+        ++hist[*it];
+
+    // Alternatively, prefer the algorithm with lambda
+    // for_each_pixel(img_view, [&hist](gray8_pixel_t const& pixel) {
+    //     ++hist[pixel];
+    // });
+}
+
+template <typename V, typename R>
+void get_hist(const V& img_view, R& hist) {
+    gray_image_hist(color_converted_view<gray8_pixel_t>(img_view), hist);
+}
+
+int main() {
+    rgb8_image_t img;
+    read_image("test.jpg", img, jpeg_tag());
+
+    int histogram[256];
+    std::fill(histogram,histogram + 256, 0);
+    get_hist(const_view(img), histogram);
+
+    std::fstream histo_file("out-histogram.txt", std::ios::out);
+    for(std::size_t ii = 0; ii < 256; ++ii)
+        histo_file << histogram[ii] << std::endl;
+    histo_file.close();
+
+    return 0;
+}