//tools.cpp
#include "stdafx.h"
#include "tools.h"
///////////////////////////////////////////////////////////////////////////////
COLORREF HLS_TRANSFORM (COLORREF rgb, int percent_L, int percent_S)
{
    HLSCOLOR hls = RGB2HLS (rgb);
    BYTE h = HLS_H(hls);
    BYTE l = HLS_L(hls);
    BYTE s = HLS_S(hls);

    if ( percent_L > 0 )
    {
        l = BYTE(l + ((255 - l) * percent_L) / 100);
    }
    else if ( percent_L < 0 )
    {
        l = BYTE((l * (100+percent_L)) / 100);
    }
    if ( percent_S > 0 )
    {
        s = BYTE(s + ((255 - s) * percent_S) / 100);
    }
    else if ( percent_S < 0 )
    {
        s = BYTE((s * (100+percent_S)) / 100);
    }
    return HLS2RGB (HLS(h, l, s));
}
///////////////////////////////////////////////////////////////////////////////
COLORREF HLS2RGB (HLSCOLOR hls)
{
    float hue        = ((int)HLS_H(hls)*360)/255.0f;
    float luminance  = HLS_L(hls)/255.0f;
    float saturation = HLS_S(hls)/255.0f;

    if ( saturation == 0.0f )
    {
        return RGB (HLS_L(hls), HLS_L(hls), HLS_L(hls));
    }
    float rm1, rm2;
     
    if ( luminance <= 0.5f ) rm2 = luminance + luminance * saturation;  
    else                     rm2 = luminance + saturation - luminance * saturation;
    rm1 = 2.0f * luminance - rm2;   
    BYTE red   = _ToRGB (rm1, rm2, hue + 120.0f);   
    BYTE green = _ToRGB (rm1, rm2, hue);
    BYTE blue  = _ToRGB (rm1, rm2, hue - 120.0f);

    return RGB (red, green, blue);
}
///////////////////////////////////////////////////////////////////////////////
static BYTE _ToRGB (float rm1, float rm2, float rh)
{
  if      (rh > 360.0f) rh -= 360.0f;
  else if (rh <   0.0f) rh += 360.0f;
 
  if      (rh <  60.0f) rm1 = rm1 + (rm2 - rm1) * rh / 60.0f;   
  else if (rh < 180.0f) rm1 = rm2;
  else if (rh < 240.0f) rm1 = rm1 + (rm2 - rm1) * (240.0f - rh) / 60.0f;      
                   
  return (BYTE)(rm1 * 255);
}
///////////////////////////////////////////////////////////////////////////////
HLSCOLOR RGB2HLS (COLORREF rgb)
{
    unsigned char minval = min(GetRValue(rgb), min(GetGValue(rgb), GetBValue(rgb)));
    unsigned char maxval = max(GetRValue(rgb), max(GetGValue(rgb), GetBValue(rgb)));
    float mdiff  = float(maxval) - float(minval);
    float msum   = float(maxval) + float(minval);
   
    float luminance = msum / 510.0f;
    float saturation = 0.0f;
    float hue = 0.0f; 

    if ( maxval != minval )
    { 
        float rnorm = (maxval - GetRValue(rgb)  ) / mdiff;      
        float gnorm = (maxval - GetGValue(rgb)) / mdiff;
        float bnorm = (maxval - GetBValue(rgb) ) / mdiff;   

        saturation = (luminance <= 0.5f) ? (mdiff / msum) : (mdiff / (510.0f - msum));

        if (GetRValue(rgb) == maxval) hue = 60.0f * (6.0f + bnorm - gnorm);
        if (GetGValue(rgb) == maxval) hue = 60.0f * (2.0f + rnorm - bnorm);
        if (GetBValue(rgb) == maxval) hue = 60.0f * (4.0f + gnorm - rnorm);
        if (hue > 360.0f) hue = hue - 360.0f;
    }
    return HLS ((hue*255)/360, luminance*255, saturation*255);
}