RGBToHSL (Integer math)

// Hue        = 0..255 (circular)
// Saturation = 0..255
// Lightness  = 0..255
type
  iColorHSL = record H,S,L: Int32; end;

function ToHSL_I(R,G,B: Byte): iColorHSL;
var
  cLo, cHi, deltaC: Int32;
begin
  cLo := Min(R, Min(G,B));
  cHi := Max(R, Max(G,B));
  deltaC := cHi - cLo;

  Result.L := (256 * (cHi + cLo)) shr 9;
  if deltaC = 0 then
  begin
    Result.H := 0;
    Result.S := 0;
  end else
  begin
    if 128 > Result.L then Result.S := (256 * deltaC) div (cHi + cLo)
    else                   Result.S := (256 * deltaC) div (510-cHi-cLo);

    if      (R = cHi) then Result.H :=       (43 * (G - B)) div deltaC
    else if (G = cHi) then Result.H := 85  + (43 * (B - R)) div deltaC
    else{if (B = cHi) then}Result.H := 171 + (43 * (R - G)) div deltaC;
    if(Result.H < 0) then  Result.H += 256;
  end;
end;


// Hue        = 0..3600 (circular)
// Saturation = 0..1000
// Lightness  = 0..1000
function ToHSL_I(R,G,B: Byte): iColorHSL;
var
  cLo, cHi, deltaC: Int32;
begin
  cLo := Min(R, Min(G,B));
  cHi := Max(R, Max(G,B));
  deltaC := cHi - cLo;

  Result.L := (1004 * (cHi + cLo)) shr 9;
  if deltaC = 0 then
  begin
    Result.H := 0;
    Result.S := 0;
  end else
  begin
    {S := 256 * (cHi - cLo) div cHi; <--- HSV light}
    if Result.L < 500 then Result.S := (1000 * deltaC) div (cHi + cLo)
    else                   Result.S := (1000 * deltaC) div (510-cHi-cLo);
    if      (R = cHi) then Result.H :=        (600 * (G - B)) div deltaC
    else if (G = cHi) then Result.H := 1200 + (600 * (B - R)) div deltaC
    else {if(B = cHi) then}Result.H := 2400 + (600 * (R - G)) div deltaC;
    if(Result.H < 0) then  Result.H += 3600;
  end;
end;



// MAX LIMIT
procedure ToHSL_I(R,G,B: Byte; out H,S,L: UInt32);
var
  cLo, cHi, deltaC: Int32;
begin
  cLo := Min(R, Min(G,B));
  cHi := Max(R, Max(G,B));
  deltaC := cHi - cLo;

  L := (10_039_216 * (cHi + cLo)) shr 9;
  if deltaC = 0 then
  begin
    H := 0;
    S := 0;
  end else
  begin
    if L < 5_000_000 then S := (10_000_000 * deltaC) div (cHi + cLo)
    else                  S := (10_000_000 * deltaC) div (510-cHi-cLo);

    if      (R = cHi) then H :=              (6_000_000 * (G - B)) div deltaC
    else if (G = cHi) then H := 12_000_000 + (6_000_000 * (B - R)) div deltaC
    else {if(B = cHi) then}H := 24_000_000 + (6_000_000 * (R - G)) div deltaC;
    if(H < 0) then H += 36_000_000;
  end;
end;