SRL Archive - Help

Anyone know how to get the Hue and Saturation from a color without using simba?

[5:53:48 PM] Olly: Kasi its called a brain sir
[5:53:56 PM] Olly: i can work out the hue/mod just by looking at a colour
[5:54:12 PM] Kasi Reddy: genius, tell me how to do it?
[5:55:23 PM] Olly: by going to school, the blue of your skype name has a hue of 0.02 and a sat mod of 1.14
[5:55:43 PM] Steven: meh
[5:55:48 PM] Steven: i dont think i could ever do that
[5:55:56 PM] Steven: mainly cause im colour blind :D

^skype chat :P
anyway tried googling it? are you able to use other programs to do this?

http://en.wikipedia.org/wiki/HSL_and_HSV#Converting_to_RGB

From: The Killer

anyway tried googling it? are you able to use other programs to do this?

Nope :(

From: mormonman
http://en.wikipedia.org/wiki/HSL_and_HSV#Converting_to_RGB

Already had a look at it, was quite confusing :S

From: Kasi
Nope :(



Already had a look at it, was quite confusing :S

Well that is the formula, here it is in simba's source: https://github.com/MerlijnWajer/Simba/blob/master/Units/MMLCore/colour_conv.pas#L205

As you can see, the integer color is first converted to rgb then to hsl.

From: mormonman
Well that is the formula, here it is in simba's source: https://github.com/MerlijnWajer/Simba/blob/master/Units/MMLCore/colour_conv.pas#L205

As you can see, the integer color is first converted to rgb then to hsl.

:P Thanks :D repped. tried looking before but couldnt find.

I explained it before. But okay, let's do it again cause I am in a good mood ^^

First you take a color, in this example (red: 222, blue: 124, green:180)

We have to convert those components to a percentage. So a number between the 0 and the 1.

redP = 222 / 255;
blueP = 124 / 255;
greenP = 180 / 255;

The we have to get the highest and lowest component. In this case:

lowComp = blueP
highComp = redP

L(lightness) can already be calculated.

L = 0.5 * (highComp + lowComp)

In this case L will be:

L = 0.5 * ((222 / 255) + (124 / 255)) = 0.72156862745098039215686274509804

We then proceed to calculate the difference between the highest and the lowest component.

Diff = highComp - lowComp

In this case that will be:

Diff = (222 / 255) - (124 / 255) = 0,48627450980392156862745098039216

if L(ligtness) is less then 0.5, the sat component can be calculated as:

sat = Diff / (highComp + lowComp)

if the color is darker, and thus L > 0.5, the sat component can be calculated as:

sat = Diff / (2 - highComp - lowComp);

In this case the color is darker, so we use the second formula.

sat = Diff / (2 - (222 / 255) - (124 / 255)) = 0,84722222…2

Jeej!!! Now the only thing to calculate is hue. This is also the hardest one, but let's see. The formula we use depends on which color is highComp.

If highComp is redP then:

hue = ((greenP - blueP ) / Diff) / 6

If highComp is greenP then:

hue = (2 + (blueP - redP ) / Diff) / 6

If highComp is blueP then:

hue = (4 + (redP - greenP ) / Diff) / 6

In this case the highComp is redP. So we use the first formule:

hue = (((180 / 255) - (124 / 255)) / Diff) / 6) = 0,07650273224043715846994535519126

The simba function(RGBToHSL):

program new;
var
  h, s, l: Extended;
  R,  G,  B,   D,  Cmax, Cmin: Extended;

begin
  R := 244 / 255;
  G := 180 / 255;
  B := 124 / 255;
  CMin := R;
  if G < Cmin then Cmin := G;
  if B  < Cmin then Cmin := B;
  CMax := R;
  if G > Cmax then Cmax := G;
  if B  > Cmax then Cmax := B;
  L := 0.5 * (Cmax + Cmin);
  if Cmax = Cmin then
  begin
    H := 0;
    S := 0;
  end else
  begin
    D := Cmax - Cmin;
    if L < 0.5 then
      S := D / (Cmax + Cmin)
    else
      S := D / (2 - Cmax - Cmin);
    if R = Cmax then
      H := (G - B) / D
    else
      if G = Cmax then
        H  := 2 + (B - R) / D
      else
        H := 4 +  (R - G) / D;
    H := H / 6;
    if H < 0 then
      H := H + 1;
  end;
  writeln(h);
  writeln(s);
  writeln(l);
end.

edit:

ninja'd. Reminder to myself, don't spend to much time replying.