struct Opal::Color

• Opal::Color
• Struct
• Value
• Object

Overview

Color model supporting 16 standard ANSI colors, 256 indexed palette, and 24-bit TrueColor RGB.

Defined in:

opal/style/color.cr

Constructors

• .ansi(code : Int32) : Color
• .cmyk(c : Float64, m : Float64, y : Float64, k : Float64) : Color

  Constructs Color from CMYK components: C, M, Y, K in [0, 1]

• .from(val : Color | Symbol | String) : Color

  Resolves a symbol or string (e.g.

• .hex(raw : String) : Color

  Parses hex string like "#ff79c6", "61AFEF", or "#fff"

• .hsl(h : Float64, s : Float64, l : Float64) : Color

  Constructs Color from HSL components: h in [0, 360], s in [0, 1], l in [0, 1]

• .hsv(h : Float64, s : Float64, v : Float64) : Color

  Constructs Color from HSV components: h in [0, 360], s in [0, 1], v in [0, 1]

• .index(code : Int32) : Color
• .lab(l : Float64, a : Float64, b : Float64) : Color

  Constructs Color from CIELAB components: L* in [0, 100], a* in [-128, 127], b* in [-128, 127]

• .lerp(c1 : Color, c2 : Color, t : Float64) : Color

  Linearly interpolates between two colors by factor t (0.0 to 1.0)

• .new(type : Type, code : Int32 = 0, r : UInt8 = 0_u8, g : UInt8 = 0_u8, b : UInt8 = 0_u8)
• .none : Color
• .oklab(l : Float64, a : Float64, b : Float64) : Color

  Constructs Color from Oklab components: L in [0, 1], a in [-0.4, 0.4], b in [-0.4, 0.4]

• .oklch(l : Float64, c : Float64, h : Float64) : Color

  Constructs Color from Oklch components: L in [0, 1], C in [0, 0.4], h in [0, 360]

• .rgb(r : Int, g : Int, b : Int) : Color
• .xyz(x : Float64, y : Float64, z : Float64) : Color

  Constructs Color from CIE XYZ components: X, Y, Z in [0, 1]

Class Method Summary

• .black

  Named color helpers

• .blue
• .bright_black
• .bright_blue
• .bright_cyan
• .bright_green
• .bright_magenta
• .bright_red
• .bright_white
• .bright_yellow
• .cyan
• .gray
• .green
• .grey
• .magenta
• .no_color? : Bool

  Checks whether colors are suppressed via NO_COLOR standard

• .red
• .white
• .yellow

Instance Method Summary

• #b : UInt8
• #bg_escape : String

  Emits the ANSI escape code for background

• #code : Int32
• #contrast_ratio(other : Color) : Float64

  Calculates WCAG 2.1 contrast ratio against another color (range 1.0 : 1 to 21.0 : 1)

• #darken(factor : Float64) : Color

  Darkens the color toward black by factor (0.0 to 1.0)

• #ensure_contrast(bg : Color, min_ratio : Float64 = 4.5) : Color

  Adjusts luminance until contrast ratio against bg meets or exceeds min_ratio

• #fg_escape : String

  Emits the ANSI escape code for foreground

• #g : UInt8
• #lighten(factor : Float64) : Color

  Lightens the color toward white by factor (0.0 to 1.0)

• #none? : Bool
• #r : UInt8
• #readable_against?(bg : Color, min_ratio : Float64 = 4.5) : Bool

  Returns true if the contrast ratio meets or exceeds the required WCAG threshold (default 4.5 for AA normal text)

• #relative_luminance : Float64

  Calculates WCAG 2.1 relative luminance (0.0 for black to 1.0 for white)

• #to_cmyk : Tuple(Float64, Float64, Float64, Float64)

  Converts Color to CMYK components: {C, M, Y, K} in [0..1]

• #to_hex : String

  Formats color as hex string "#RRGGBB"

• #to_hsl : Tuple(Float64, Float64, Float64)

  Converts Color to HSL components: {H [0..360], S [0..1], L [0..1]}

• #to_hsv : Tuple(Float64, Float64, Float64)

  Converts Color to HSV components: {H [0..360], S [0..1], V [0..1]}

• #to_lab : Tuple(Float64, Float64, Float64)

  Converts Color to CIELAB components: {L* [0..100], a* [-128..127], b* [-128..127]}

• #to_oklab : Tuple(Float64, Float64, Float64)

  Converts Color to Oklab components: {L [0..1], a [-0.4..0.4], b [-0.4..0.4]}

• #to_oklch : Tuple(Float64, Float64, Float64)

  Converts Color to Oklch components: {L [0..1], C [0..0.4], h [0..360]}

• #to_rgb : Tuple(UInt8, UInt8, UInt8)

  Converts color to RGB tuple (approximate for ANSI)

• #to_xyz : Tuple(Float64, Float64, Float64)

  Converts Color to CIE XYZ components: {X, Y, Z} in [0..1]

• #type : Type
• #write_bg_escape(io : IO) : Nil

  Writes background ANSI escape sequence directly to an IO without intermediate String allocations

• #write_fg_escape(io : IO) : Nil

  Writes foreground ANSI escape sequence directly to an IO without intermediate String allocations

Constructor Detail

Class Method Detail

Instance Method Detail