ceph/src/boost/libs/gil/example/histogram.cpp

   1 /*
   2     Copyright 2005-2007 Adobe Systems Incorporated
   3
   4     Use, modification and distribution are subject to the Boost Software License,
   5     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   6     http://www.boost.org/LICENSE_1_0.txt).
   7
   8     See http://opensource.adobe.com/gil for most recent version including documentation.
   9 */
  10
  11 /*************************************************************************************************/
  12
  13 /// \file
  14 /// \brief Example file to demonstrate a way to compute histogram
  15 /// \author Lubomir Bourdev and Hailin Jin
  16 /// \date February 27, 2007
  17
  18 #include <algorithm>
  19 #include <fstream>
  20 #include <boost/gil/image.hpp>
  21 #include <boost/gil/typedefs.hpp>
  22 #include <boost/gil/color_convert.hpp>
  23 #include <boost/gil/extension/io/jpeg_io.hpp>
  24
  25 using namespace boost::gil;
  26
  27 template <typename GrayView, typename R>
  28 void gray_image_hist(const GrayView& img_view, R& hist) {
  29 //    for_each_pixel(img_view,++lambda::var(hist)[lambda::_1]);
  30     for (typename GrayView::iterator it=img_view.begin(); it!=img_view.end(); ++it)
  31         ++hist[*it];
  32 }
  33
  34 template <typename V, typename R>
  35 void get_hist(const V& img_view, R& hist) {
  36     gray_image_hist(color_converted_view<gray8_pixel_t>(img_view), hist);
  37 }
  38
  39 int main() {
  40     rgb8_image_t img;
  41     jpeg_read_image("test.jpg",img);
  42
  43     int histogram[256];
  44     std::fill(histogram,histogram+256,0);
  45     get_hist(const_view(img),histogram);
  46
  47     std::fstream histo_file("out-histogram.txt",std::ios::out);
  48     for(std::size_t ii=0;ii<256;++ii)
  49         histo_file << histogram[ii] << std::endl;
  50     histo_file.close();
  51
  52     return 0;
  53 }