Function showHistogramWindow

example/opencv_histogram.cpp:73–119

);

inline void showHistogramWindow(cv::Mat &b_hist, cv::Mat &g_hist, cv::Mat &r_hist,
                         std::string window_name)
{
    // Draw the histograms for B, G and R
    int hist_w = 1024;
    int hist_h = 768;
    int bin_w = cvRound((double)hist_w/histSize);

    cv::Mat histImage(hist_h, hist_w, CV_8UC3, cv::Scalar(0,0,0));

    // Normalize the result to [ 0, histImage.rows ]
    cv::normalize(b_hist, b_hist, 0, histImage.rows, cv::NORM_MINMAX, -1, cv::Mat());
    cv::normalize(g_hist, g_hist, 0, histImage.rows, cv::NORM_MINMAX, -1, cv::Mat());
    cv::normalize(r_hist, r_hist, 0, histImage.rows, cv::NORM_MINMAX, -1, cv::Mat());

    // Draw for each channel
    for (int i = 1; i < histSize; i++ )
    {
        cv::line(histImage,
                 cv::Point(bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1))),
                 cv::Point(bin_w*(i), hist_h - cvRound(b_hist.at<float>(i))),
                 cv::Scalar(255, 0, 0),
                 2,
                 8,
                 0);

        cv::line(histImage,
                 cv::Point(bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1))),
                 cv::Point(bin_w*(i), hist_h - cvRound(g_hist.at<float>(i))),
                 cv::Scalar(0, 255, 0),
                 2,
                 8,
                 0);

        cv::line(histImage,
                 cv::Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1))),
                 cv::Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
                 cv::Scalar( 0, 0, 255),
                 2,
                 8,
                 0);
    }

    // Display
    cv::namedWindow(window_name, CV_WINDOW_AUTOSIZE );
    cv::imshow(window_name, histImage );
}

//Get the device context
//Create GPU array/vector