Lightness out of range #106
Description
There is a test in svgtypes for when HSL values are out of range from parse time.
It expects hsl(800, 150%, -50%) to result in rgba(0, 0, 0, 255) as the lightness is clamped to 0, and so the value is a black color.
While the CSS Color Module 4 spec says that, when parsing HSL, saturation is clamped, it does not say it about lightness.
- Section 4.2 does say to clamp alpha.
- Section 5.1 does say to clamp r, g, and b when parsing
rgb(). - Section 7 says to clamp saturation for HSL.
- Section 9.3 says to clamp L for Lab and Lch.
- Section 9.4 says to clamp L for OkLab and OkLch.
- Section 13.2 says that when gamut mapping to ran rgb destination, the out of range lightness values should be handled by resulting in either black or white colors.
Even if we clamp at parse time, we'd have to think also about what to do when the lightness has been modified (like via map_lightness) and is now out of range due to calculations.