README.md

colorgrad 🎨

Fun & easy way to create color gradient / color scales in Go (Golang).

Index

• Usages
  • Basic
  • Custom Colors
  • Hex Colors
  • Named Colors
  • Custom Domain
  • Blending Mode
  • Invalid RGB
  • Hard-Edged Gradient
• Preset Gradients
• Color Scheme
• Gallery
• Playground
• Dependencies
• Inspirations

Usages

Basic

import "github.com/mazznoer/colorgrad"

grad, err := colorgrad.NewGradient().Build()

if err != nil {
    panic(err)
}

// Get single color at certain position.
grad.At(0) // colorful.Color
grad.At(0.5).Hex() // hex color string
grad.At(1)

// Get n colors evenly spaced across gradient.
grad.Colors(27) // []colorful.Color
colorgrad.IntoColors(grad.Colors(10)) // []color.Color

Custom Colors

Colors() method accept anything that implement color.Color interface.

import "image/color"
import "github.com/lucasb-eyer/go-colorful"

grad, err := colorgrad.NewGradient().
    Colors(
        color.RGBA{0, 206, 209, 255},
        color.RGBA{255, 105, 180, 255},
        colorful.Color{R: 0.274, G: 0.5, B: 0.7},
        colorful.Hsv(50, 1, 1),
        colorful.Hsv(348, 0.9, 0.8),
    ).
    Mode(colorgrad.HCL).
    Build()

Using Hex Colors

grad, err := colorgrad.NewGradient().
    HtmlColors("#FFD700", "#00BFFF", "#FFD700").
    Build()

Named Colors

We can also use named colors as defined in the SVG 1.1 spec.

grad, err := colorgrad.NewGradient().
    HtmlColors("gold", "hotpink", "darkturquoise").
    Build()

Custom Domain

grad, err := colorgrad.NewGradient().
    HtmlColors("#DC143C", "#FFD700", "#4682b4").
    Build()

grad, err := colorgrad.NewGradient().
    HtmlColors("#DC143C", "#FFD700", "#4682b4").
    Domain(0, 0.35, 1).
    Build()

grad, err := colorgrad.NewGradient().
    HtmlColors("#DC143C", "#FFD700", "#4682b4").
    Domain(15, 60, 80).
    Build()

grad.At(15).Hex() // #DC143C
grad.At(75)
grad.At(80).Hex() // #4682b4

Blending Mode

grad, err := colorgrad.NewGradient().
    HtmlColors("#ff0", "#008ae5").
    Mode(colorgrad.LRGB).
    Build()

Beware of Invalid RGB Color

Read it here.

grad, err := colorgrad.NewGradient().
    HtmlColors("#DC143C", "#FFD700", "#4682b4").
    Mode(colorgrad.HCL).
    Build()

grad.At(t) // might get invalid RGB color
grad.At(t).Clamped() // return closest valid RGB color

Without Clamped()

With Clamped()

Hard-Edged Gradient

grad1, err := colorgrad.NewGradient().
    HtmlColors("#18dbf4", "#f6ff56").
    Domain(0, 100).
    Build()

grad2 := colorgrad.SharpGradient(grad1, 7)

Note: Result gradient from SharpGradient() will always in the range 0..1.

Preset Gradients

grad := colorgrad.Rainbow()
grad.At(t) // t in the range 0..1
grad.Colors(15)

Diverging

colorgrad.BrBG()

colorgrad.PRGn()

colorgrad.PiYG()

colorgrad.PuOr()

colorgrad.RdBu()

colorgrad.RdGy()

colorgrad.RdYlBu()

colorgrad.RdYlGn()

colorgrad.Spectral()

Sequential (Single Hue)

colorgrad.Blues()

colorgrad.Greens()

colorgrad.Greys()

colorgrad.Oranges()

colorgrad.Purples()

colorgrad.Reds()

Sequential (Multi-Hue)

colorgrad.Turbo()

colorgrad.Viridis()

colorgrad.Inferno()

colorgrad.Magma()

colorgrad.Plasma()

colorgrad.Cividis()

colorgrad.Warm()

colorgrad.Cool()

colorgrad.CubehelixDefault()

Cyclical

colorgrad.Rainbow()

colorgrad.Sinebow()

Color Scheme

colorgrad.Scheme.Accent

colorgrad.Scheme.Category10

colorgrad.Scheme.Dark2

colorgrad.Scheme.Paired

colorgrad.Scheme.Pastel1

colorgrad.Scheme.Pastel2

colorgrad.Scheme.Set1

colorgrad.Scheme.Set2

colorgrad.Scheme.Set3

Gallery

Noise + hard-edged gradient

Random cool colors

Playground

• Basic
• Random colors

Dependencies

• colorful

Inspirations

• chroma.js
• d3-scale-chromatic