ColorSpaces.h

// Color Space Transformation Class
// Written by Sergey G. Kosov in 2008 for MPII
// Extended by Sergey G. Kosov in 2014 - 2016 for Project X
#pragma once

#include "types.h"

#define DGM_HSV(h, s, v) cv::Scalar(h, s, v, 0 )

namespace DirectGraphicalModels { namespace vis
{
    namespace colorspaces {
        inline cv::Scalar rgb2bgr(cv::Scalar rgb)
        {
            cv::Scalar bgr;
            bgr.val[0] = rgb.val[2];
            bgr.val[1] = rgb.val[1];
            bgr.val[2] = rgb.val[0];
            bgr.val[3] = rgb.val[3];
            return bgr;
        }
        inline cv::Scalar bgr2rgb(cv::Scalar bgr) { return rgb2bgr(bgr); }
        inline cv::Scalar hsv2bgr(cv::Scalar hsv)
        {
            double      hh, p, q, t, ff;
            long        i;
            cv::Scalar  out;

            if (hsv.val[1] <= 0.0) {            // < is bogus, just shuts up warnings
                out.val[0] = hsv.val[2];
                out.val[1] = hsv.val[2];
                out.val[2] = hsv.val[2];
                return out;
            }
            hh = hsv.val[0];
            if (hh >= 360.0) hh = 0.0;
            hh /= 60.0;
            i = (long)hh;
            ff = hh - i;
            p = hsv.val[2] * (1.0 - hsv.val[1] / 255.0);
            q = hsv.val[2] * (1.0 - (hsv.val[1] * ff) / 255.0);
            t = hsv.val[2] * (1.0 - (hsv.val[1] * (1.0 - ff)) / 255.0);

            switch (i) {
            case 0:
                out.val[0] = hsv.val[2];
                out.val[1] = t;
                out.val[2] = p;
                break;
            case 1:
                out.val[0] = q;
                out.val[1] = hsv.val[2];
                out.val[2] = p;
                break;
            case 2:
                out.val[0] = p;
                out.val[1] = hsv.val[2];
                out.val[2] = t;
                break;

            case 3:
                out.val[0] = p;
                out.val[1] = q;
                out.val[2] = hsv.val[2];
                break;
            case 4:
                out.val[0] = t;
                out.val[1] = p;
                out.val[2] = hsv.val[2];
                break;
            case 5:
            default:
                out.val[0] = hsv.val[2];
                out.val[1] = p;
                out.val[2] = q;
                break;
            }
            return out;
        }
        inline cv::Scalar hsv2rgb(cv::Scalar hsv) { return bgr2rgb(hsv2bgr(hsv)); }
    }
} }