colorgrad
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Go (Golang) color scales library for data visualization, charts, games, maps, generative art and others.
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Index
import "github.com/mazznoer/colorgrad"
Custom Gradient
Basic
grad, err := colorgrad.NewGradient().Build()
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Custom Colors
grad, err := colorgrad.NewGradient().
Colors(
colorgrad.Rgb8(0, 206, 209, 255),
colorgrad.Rgb8(255, 105, 180, 255),
colorgrad.Rgb(0.274, 0.5, 0.7, 1),
colorgrad.Hsv(50, 1, 1, 1),
colorgrad.Hsv(348, 0.9, 0.8, 1),
).
Build()
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Using Web Color Format
HtmlColors()
method accepts named colors, hexadecimal (#rgb
, #rgba
, #rrggbb
, #rrggbbaa
), rgb()
, rgba()
, hsl()
, hsla()
, hwb()
, and hsv()
.
grad, err := colorgrad.NewGradient().
HtmlColors("#C41189", "#00BFFF", "#FFD700").
Build()
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grad, err := colorgrad.NewGradient().
HtmlColors("gold", "hotpink", "darkturquoise").
Build()
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grad, err := colorgrad.NewGradient().
HtmlColors(
"rgb(125,110,221)",
"rgb(90%,45%,97%)",
"hsl(229,79%,85%)",
).
Build()
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Domain & Color Position
Default domain is [0..1].
grad, err := colorgrad.NewGradient().
HtmlColors("deeppink", "gold", "seagreen").
Build()
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Set the domain to [0..100].
grad, err := colorgrad.NewGradient().
HtmlColors("deeppink", "gold", "seagreen").
Domain(0, 100).
Build()
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Set the domain to [-1..1].
grad, err := colorgrad.NewGradient().
HtmlColors("deeppink", "gold", "seagreen").
Domain(-1, 1).
Build()
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Set exact position for each color. The domain is [0..1].
grad, err := colorgrad.NewGradient().
HtmlColors("deeppink", "gold", "seagreen").
Domain(0, 0.7, 1).
Build()
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Set exact position for each color. The domain is [15..80].
grad, err := colorgrad.NewGradient().
HtmlColors("deeppink", "gold", "seagreen").
Domain(15, 30, 80).
Build()
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Blending Mode
grad, err := colorgrad.NewGradient().
HtmlColors("#FFF", "#00F").
Mode(colorgrad.BlendRgb).
Build()
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Interpolation Mode
grad, err := colorgrad.NewGradient().
HtmlColors("#C41189", "#00BFFF", "#FFD700").
Interpolation(colorgrad.InterpolationLinear).
Build()
InterpolationLinear
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InterpolationCatmullRom
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InterpolationBasis
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Preset Gradients
See PRESET.md
Parsing GIMP Gradient
import "os"
foreground := colorgrad.Rgb(0, 0, 0, 1)
background := colorgrad.Rgb(1, 1, 1, 1)
file, err := os.Open("Abstract_1.ggr")
if err != nil {
panic(err)
}
defer file.Close()
grad, name, err2 := colorgrad.ParseGgr(file, foreground, background)
fmt.Println(name)
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Using the Gradient
Get the domain
grad := colorgrad.Rainbow()
fmt.Println(grad.Domain())
Get single color at certain position
grad := colorgrad.Rainbow()
fmt.Println(grad.At(0.0).HexString())
fmt.Println(grad.At(0.5).HexString())
fmt.Println(grad.At(1.0).HexString())
Get n colors evenly spaced across gradient
grad := colorgrad.Rainbow()
for _, c := range grad.Colors(10) {
fmt.Println(c.HexString())
}
Output:
#6e40aa
#c83dac
#ff5375
#ff8c38
#c9d33a
#7cf659
#5dea8d
#48b8d0
#4775de
#6e40aa
Hard-Edged Gradient
Convert gradient to hard-edged gradient with 11 segments and 0 smoothness.
grad := colorgrad.Rainbow().Sharp(11, 0)
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This is the effect of different smoothness.
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Examples
Gradient Image
package main
import (
"image"
"image/png"
"os"
"github.com/mazznoer/colorgrad"
)
func main() {
grad, _ := colorgrad.NewGradient().
HtmlColors("#C41189", "#00BFFF", "#FFD700").
Build()
w := 1500
h := 70
fw := float64(w)
img := image.NewRGBA(image.Rect(0, 0, w, h))
for x := 0; x < w; x++ {
col := grad.At(float64(x) / fw)
for y := 0; y < h; y++ {
img.Set(x, y, col)
}
}
file, err := os.Create("gradient.png")
if err != nil {
panic(err.Error())
}
defer file.Close()
png.Encode(file, img)
}
Example output:
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Colored Noise
package main
import (
"image"
"image/png"
"os"
"github.com/mazznoer/colorgrad"
"github.com/ojrac/opensimplex-go"
)
func main() {
w := 600
h := 350
scale := 0.02
grad := colorgrad.Rainbow().Sharp(7, 0.2)
noise := opensimplex.NewNormalized(996)
img := image.NewRGBA(image.Rect(0, 0, w, h))
for y := 0; y < h; y++ {
for x := 0; x < w; x++ {
t := noise.Eval2(float64(x)*scale, float64(y)*scale)
img.Set(x, y, grad.At(t))
}
}
file, err := os.Create("noise.png")
if err != nil {
panic(err.Error())
}
defer file.Close()
png.Encode(file, img)
}
Example output:
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Playground
Dependencies
Inspirations
Links