In CSS, can HSL values be floats?

Question

The CSS3 spec only specifies that:

The format of an HSLA color value in the functional notation is ‘hsla(’ followed by the hue in degrees, saturation and lightness as a percentage, and an , followed by ‘)’.

So am I to understand that these values would be interpreted not as integers but as floats? Example:

hsla(200.2, 90.5%, 10.2%, .2)

That would dramatically expand the otherwise small (relative to RGB) range of colors covered by HSL.

It seems to render fine in Chrome, though I don't know if they simply parse it as an INT value or what.

Answer 1

HSL values are converted to hexadecimal RGB values before they are handed off to the system. It's up to the device to clip any resulting RGB value that is outside the "device gamut" - the range of colors that can be displayed - to a displayable value. RGB values are denoted in Hexadecimal. This is the specified algorithm for browsers to convert HSL values to RGB values. Rounding behavior is not specified by the standard - and there are multiple ways of doing rounding since there doesn't appear to be a built-in rounding function in either C or C++.

Click to copy

HOW TO RETURN hsl.to.rgb(h, s, l): 
       SELECT: 
      l<=0.5: PUT l*(s+1) IN m2
      ELSE: PUT l+s-l*s IN m2
       PUT l*2-m2 IN m1
       PUT hue.to.rgb(m1, m2, h+1/3) IN r
       PUT hue.to.rgb(m1, m2, h    ) IN g
       PUT hue.to.rgb(m1, m2, h-1/3) IN b
       RETURN (r, g, b)

From the proposed recommendation

In other words, you should be able to represent the exact same range of colors in HSLA as you can represent in RGB using fractional values for HSLA.

Answer 2

AFAIK, every browser casts them to INTs. Maybe. If I'm wrong you won't be able to tell the difference anyway. If it really matters, why not just go take screenshots an open them in photoshop or use an on-screen color meter. Nobody here is going to have a definitive answer without testing it, and it takes 2 minutes to test... so...