contrastRatio static method

double contrastRatio(
  1. Color a,
  2. Color b
)

WCAG 2 contrast ratio between two opaque colours (1 to 21).

Implementation

static double contrastRatio(Color a, Color b) {
  final la = a.computeLuminance();
  final lb = b.computeLuminance();
  final hi = la > lb ? la : lb;
  final lo = la > lb ? lb : la;
  return (hi + 0.05) / (lo + 0.05);
}