Template:RGBtoHSL.S/doc

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This is a documentation subpage for Template:RGBtoHSL.S (see that page for the template itself).
It contains usage information, categories and other content that is not part of the original template page.

This template computes the saturation value in [0..1] in the HSL color space (as defined in standard CSS3), from a color specified in the sRGB color space. The returned value is rounded to three decimals (which preserves the precision of RGB colors whose components are specified in the standard range [0..255]).

Syntax
{{RGBtoHSL.S|r|g|b}}
The range of the three parameters is [0..255] ; they can be any numeric expressions.
{{subst:RGBtoHSL.S|r|g|b|subst=subst:}}
To substitute the template invokation by the compute value when saving an article Wiki source.
Algorithm used
if r = g and g = b then
S = 0;
else if g >= r and g >= b then
if r > b
then if g + b > 255 then S = (g - b) / (510 - g - b); else S = (g - b) / (g + b);
else if g + r > 255 then S = (g - r) / (510 - g - r); else S = (g - r) / (g + r);
else if r >= b and r >= g then
if r > g
then if r + g > 255 then S = (r - g) / (510 - r - g); else S = (r - g) / (r + g);
else if r + b > 255 then S = (r - b) / (510 - r - b); else S = (r - b) / (r + b);
else
if g > r
then if b + r > 255 then S = (b - r) / (510 - b - r); else S = (b - r) / (b + r);
else if b + g > 255 then S = (b - g) / (510 - b - g); else S = (b - g) / (b + g);
return S round 3;
Examples
  • "{{RGBtoHSL.S|0|0|0}}" returns "0".
  • "{{RGBtoHSL.S|255|255|255}}" returns "0".
  • "{{RGBtoHSL.S|255|0|0}}" returns "1".
  • "{{RGBtoHSL.S|255|1|0}}" returns "1".
  • "{{RGBtoHSL.S|255|127.5|0}}" returns "1".
  • "{{RGBtoHSL.S|255|255|0}}" returns "1".
  • "{{RGBtoHSL.S|127.5|255|0}}" returns "1".
  • "{{RGBtoHSL.S|0|255|0}}" returns "1".
  • "{{RGBtoHSL.S|0|255|127.5}}" returns "1".
  • "{{RGBtoHSL.S|0|255|255}}" returns "1".
  • "{{RGBtoHSL.S|0|127.5|255}}" returns "1".
  • "{{RGBtoHSL.S|0|0|255}}" returns "1".
  • "{{RGBtoHSL.S|127.5|0|255}}" returns "1".
  • "{{RGBtoHSL.S|255|0|255}}" returns "1".
  • "{{RGBtoHSL.S|255|0|127.5}}" returns "1".
  • "{{RGBtoHSL.S|255|0|1}}" returns "1".
  • example for "sandybrown" = "#F4A460" = "rgb(244, 164, 96)" = "hsl(27.6, 0.871, 0.667)"
"{{RGBtoHSL.S|244|164|96}}" returns "0.871".
  • same example using subst
"{{subst:RGBtoHSL.S|244|164|96|subst=subst:}}" returns "0.871".


See also