ratioOfYs
Contrast ratio is a measure of legibility, its used to compare the lightness of two colors. This method is used commonly in industry due to its use by WCAG.
To compare lightness, the colors are expressed in the XYZ color space, where Y is lightness, also known as relative luminance.
The equation is ratio = lighter Y + 5 / darker Y + 5.
Return
Contrast ratio of two colors.
Parameters
y1
Y in XYZ, relative luminance.
y2
Y in XYZ, relative luminance.