contrastRatio static method
The WCAG contrast ratio between a and b, in the range [1, 21].
Order of arguments does not matter.
Implementation
static double contrastRatio(Color a, Color b) {
final luminanceA = relativeLuminance(a);
final luminanceB = relativeLuminance(b);
final lighter = math.max(luminanceA, luminanceB);
final darker = math.min(luminanceA, luminanceB);
return (lighter + 0.05) / (darker + 0.05);
}