csscolorparser

README

Go Language CSS Color Parser Library

Go library for parsing CSS color string as defined in the W3C's CSS Color Module Level 4.

Supported Color Format

• Named colors
• RGB hexadecimal (with and without # prefix)
  • Short format #rgb
  • Short format with alpha #rgba
  • Long format #rrggbb
  • Long format with alpha #rrggbbaa
• rgb() and rgba()
• hsl() and hsla()
• hwb()
• oklab()
• oklch()
• hwba(), hsv(), hsva() - not in CSS standard.

Not yet supported: lab(), lch().

Example Color Format

transparent
lime
#0f0
#0f0f
#00ff00
#00ff00ff
rgb(0,255,0)
rgb(0% 100% 0%)
rgb(0 255 0 / 100%)
rgba(0,255,0,1)
hsl(120,100%,50%)
hsl(120deg 100% 50%)
hsl(-240 100% 50%)
hsl(-240deg 100% 50%)
hsl(0.3333turn 100% 50%)
hsl(133.333grad 100% 50%)
hsl(2.0944rad 100% 50%)
hsla(120,100%,50%,100%)
hwb(120 0% 0%)
hwb(480deg 0% 0% / 100%)
hsv(120,100%,100%)
hsv(120deg 100% 100% / 100%)

Usage Examples

import "github.com/mazznoer/csscolorparser"

c, err := csscolorparser.Parse("gold")

if err != nil {
    panic(err)
}

fmt.Printf("R:%.3f, G:%.3f, B:%.3f, A:%.3f", c.R, c.G, c.B, c.A) // R:1.000, G:0.843, B:0.000, A:1.000
fmt.Println(c.RGBA255())   // 255 215 0 255
fmt.Println(c.HexString()) // #ffd700
fmt.Println(c.RGBString()) // rgb(255,215,0)

Try It Online

• Playground 1
• Playground 2

Similar Projects

• csscolorparser (Rust)
• csscolorparser (Javascript)

Documentation

Overview

Package csscolorparser provides function for parsing CSS color string as defined in the W3C's CSS color module level 4.

Example (NamedColor)

package main

import (
	"fmt"

	"github.com/mazznoer/csscolorparser"
)

func main() {
	c, err := csscolorparser.Parse("gold")

	if err != nil {
		panic(err)
	}

	fmt.Printf("R:%.3f, G:%.3f, B:%.3f, A:%.3f\n", c.R, c.G, c.B, c.A)
	fmt.Println(c.RGBA255())
	fmt.Println(c.HexString())
	fmt.Println(c.RGBString())
}

Output:

R:1.000, G:0.843, B:0.000, A:1.000
255 215 0 255
#ffd700
rgb(255,215,0)

Example (RgbColor)

package main

import (
	"fmt"

	"github.com/mazznoer/csscolorparser"
)

func main() {
	c, err := csscolorparser.Parse("rgba(100%, 0%, 0%, 0.5)")

	if err != nil {
		panic(err)
	}

	fmt.Printf("R:%.3f, G:%.3f, B:%.3f, A:%.3f\n", c.R, c.G, c.B, c.A)
	fmt.Println(c.RGBA255())
	fmt.Println(c.HexString())
	fmt.Println(c.RGBString())
}

Output:

R:1.000, G:0.000, B:0.000, A:0.500
255 0 0 128
#ff000080
rgba(255,0,0,0.5)

Index

• type Color
  • func FromHsl(h, s, l, a float64) Color
  • func FromHsv(h, s, v, a float64) Color
  • func FromHwb(h, w, b, a float64) Color
  • func FromLinearRGB(r, g, b, a float64) Color
  • func FromOklab(l, a, b, alpha float64) Color
  • func FromOklch(l, c, h, alpha float64) Color
  • func Parse(s string) (Color, error)
  • func (c Color) Clamp() Color
  • func (c Color) HexString() string
  • func (c Color) MarshalText() ([]byte, error)
  • func (c Color) Name() (string, bool)
  • func (c Color) RGBA() (r, g, b, a uint32)
  • func (c Color) RGBA255() (r, g, b, a uint8)
  • func (c Color) RGBString() string
  • func (c *Color) UnmarshalText(text []byte) error

Examples

• Package (NamedColor)
• Package (RgbColor)

Types

type Color

type Color struct {
	R, G, B, A float64
}

R, G, B, A values in the range 0..1

func FromHsl

func FromHsl(h, s, l, a float64) Color

func FromHsv

func FromHsv(h, s, v, a float64) Color

func FromHwb

func FromHwb(h, w, b, a float64) Color

func FromLinearRGB

func FromLinearRGB(r, g, b, a float64) Color

func FromOklab

func FromOklab(l, a, b, alpha float64) Color

func FromOklch

func FromOklch(l, c, h, alpha float64) Color

func Parse

func Parse(s string) (Color, error)

Parse parses CSS color string and returns, if successful, a Color.

func (Color) Clamp

func (c Color) Clamp() Color

func (Color) HexString

func (c Color) HexString() string

HexString returns CSS hexadecimal string.

func (Color) MarshalText

func (c Color) MarshalText() ([]byte, error)

Implement the Go TextMarshaler interface

func (Color) Name

func (c Color) Name() (string, bool)

Name returns name of this color if its available.

func (Color) RGBA

func (c Color) RGBA() (r, g, b, a uint32)

Implement the Go color.Color interface.

func (Color) RGBA255

func (c Color) RGBA255() (r, g, b, a uint8)

RGBA255 returns R, G, B, A values in the range 0..255

func (Color) RGBString

func (c Color) RGBString() string

RGBString returns CSS RGB string.

func (*Color) UnmarshalText

func (c *Color) UnmarshalText(text []byte) error

Implement the Go TextUnmarshaler interface