Finds an accessible color pair (foreground/background) based on a base color and WCAG level.

Tries to find a contrasting color (black or white first) that meets the desired level.

Parameters:

• base_color: The Color struct or hex string to find a contrasting pair for.
• level: The minimum WCAG contrast ratio level (:aa or :aaa, defaults to :aa).

Returns: A tuple {foreground_color, background_color} where one is the base_color and the other is a contrasting color (typically black or white) that meets the specified level. Returns nil if no suitable pair is found immediately (further logic might be needed for complex cases).

Calculates the contrast ratio between two colors according to WCAG guidelines.

Parameters

• color1 - The first color (hex string or Color struct)
• color2 - The second color (hex string or Color struct)

Returns

• A float representing the contrast ratio (1:1 to 21:1)

Examples

iex> Raxol.Style.Colors.Accessibility.contrast_ratio("#000000", "#FFFFFF")
21.0

iex> Raxol.Style.Colors.Accessibility.contrast_ratio("#777777", "#999999")
1.3

@spec darken_until_contrast(
  Raxol.Style.Colors.Color.t(),
  Raxol.Style.Colors.Color.t(),
  number()
) ::
  Raxol.Style.Colors.Color.t()

Darkens a color until it meets the specified contrast ratio with a background color.

Requires HSL module for darken function.

Parameters

• color - The color to darken (Color struct)
• background - The background color (Color struct)
• target_ratio - The target contrast ratio to achieve

Returns

• A Color struct representing the darkened color

@spec readable?(
  Raxol.Style.Colors.Color.t() | String.t(),
  Raxol.Style.Colors.Color.t() | String.t(),
  :aa | :aaa | :aa_large | :aaa_large
) :: boolean()

Checks if a foreground color is readable on a background color.

Parameters

• background - Background color
• foreground - Text color
• level - Accessibility level (:aa, :aaa, :aa_large, :aaa_large)

Examples

iex> bg = Raxol.Style.Colors.Color.from_hex("#333333")
iex> fg = Raxol.Style.Colors.Color.from_hex("#FFFFFF")
iex> Raxol.Style.Colors.Accessibility.readable?(bg, fg)
true

iex> bg = Raxol.Style.Colors.Color.from_hex("#CCCCCC")
iex> fg = Raxol.Style.Colors.Color.from_hex("#999999")
iex> Raxol.Style.Colors.Accessibility.readable?(bg, fg, :aaa)
false

Calculates the relative luminance of a color according to WCAG guidelines.

Parameters

• color - The color to calculate luminance for (hex string or Color struct)

Returns

• A float between 0 and 1 representing the relative luminance

Examples

iex> Raxol.Style.Colors.Accessibility.relative_luminance("#000000")
0.0

iex> Raxol.Style.Colors.Accessibility.relative_luminance("#FFFFFF")
1.0

Suggests a color with good contrast (at least AA) to the base color.

Prioritizes complementary color, then black/white.

Parameters

• color - The base color (hex string or Color struct)

Examples

iex> color = Raxol.Style.Colors.Color.from_hex("#3366CC")
iex> contrast_color = Raxol.Style.Colors.Accessibility.suggest_contrast_color(color)
iex> Raxol.Style.Colors.Accessibility.readable?(color, contrast_color)
true

Suggests an appropriate text color (black or white) for a given background.

Ensures minimum AA contrast.

Parameters

• background - The background color (hex string or Color struct)

Examples

iex> Raxol.Style.Colors.Accessibility.suggest_text_color("#333333").hex
"#FFFFFF"

iex> Raxol.Style.Colors.Accessibility.suggest_text_color("#EEEEEE").hex
"#000000"