Module: ColorContrastCalc::TransparencyCalc

Includes:
Converter::AlphaCompositing::Rgba
Defined in:
lib/color_contrast_calc/transparency_calc.rb

Overview

Provides methods to calculate the contrast ratio between transparent colors.

Colors are given as RGBA values represented as arrays of Float. Note that during the process of calculation, each of RGB components is treated as a Float, though some of them may be rounded up/down in the final return value.

Constant Summary

Constants included from Converter::AlphaCompositing::Rgba

Converter::AlphaCompositing::Rgba::BLACK, Converter::AlphaCompositing::Rgba::WHITE

Class Method Summary collapse

Class Method Details

.contrast_ratio(foreground, background, base = WHITE) ⇒ Object 



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# File 'lib/color_contrast_calc/transparency_calc.rb', line 18

def self.contrast_ratio(foreground, background, base = WHITE)
  colors = [foreground, background]

  rgb_colors = if colors.all? {|color| opaque?(color) }
                 colors.map {|color| to_rgb(color) }
               else
                 to_opaque_rgbs(foreground, background, base)
               end

  Checker.contrast_ratio(*rgb_colors)
end