Added OKLCH color space

Benchmarks_test.go

@@ -13,7 +13,23 @@ func BenchmarkRGB(b *testing.B) {
 	}
 }
 
-func BenchmarkFprint(b *testing.B) {
+func BenchmarkLCH(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		color.LCH(0.5, 0.5, 0.0)
+	}
+}
+
+func BenchmarkFprintColorized(b *testing.B) {
+	color.Terminal = true
+	c := color.RGB(1.0, 1.0, 1.0)
+
+	for i := 0; i < b.N; i++ {
+		c.Fprint(io.Discard, "")
+	}
+}
+
+func BenchmarkFprintRaw(b *testing.B) {
+	color.Terminal = false
 	c := color.RGB(1.0, 1.0, 1.0)
 
 	for i := 0; i < b.N; i++ {

Color.go

@@ -5,18 +5,18 @@ import (
 	"io"
 )
 
-// Component is a type definition for the data type of a single color component.
-type Component float32
+// Value is a type definition for the data type of a single color component.
+type Value = float64
 
 // Color represents an RGB color.
 type Color struct {
-	R Component
-	G Component
-	B Component
+	R Value
+	G Value
+	B Value
 }
 
 // RGB creates a new color with red, green and blue values in the range of 0.0 to 1.0.
-func RGB(r Component, g Component, b Component) Color {
+func RGB(r Value, g Value, b Value) Color {
 	return Color{r, g, b}
 }
 

Color_test.go

@@ -1,6 +1,7 @@
 package color_test
 
 import (
+	"fmt"
 	"io"
 	"testing"
 
@@ -8,36 +9,73 @@ import (
 	"git.akyoto.dev/go/color"
 )
 
-func TestColors(t *testing.T) {
-	color.Terminal = true
-	testColors(t)
-}
-
 func TestNoColors(t *testing.T) {
 	color.Terminal = false
-	testColors(t)
+	testRGBColors(t)
+	testLCHColors(t)
 }
 
-func testColors(t *testing.T) {
-	colors := map[string]color.Color{
-		"black": color.RGB(0.0, 0.0, 0.0),
-		"white": color.RGB(1.0, 1.0, 1.0),
-		"red":   color.RGB(1.0, 0.0, 0.0),
-		"green": color.RGB(0.0, 1.0, 0.0),
-		"blue":  color.RGB(0.0, 0.0, 1.0),
-	}
+func TestColors(t *testing.T) {
+	color.Terminal = true
+	testRGBColors(t)
+	testLCHColors(t)
+}
 
-	for name, value := range colors {
-		assert.True(t, value.R >= 0.0)
-		assert.True(t, value.G >= 0.0)
-		assert.True(t, value.B >= 0.0)
+func TestRainbow(t *testing.T) {
+	color.Terminal = true
 
-		assert.True(t, value.R <= 1.0)
-		assert.True(t, value.G <= 1.0)
-		assert.True(t, value.B <= 1.0)
+	for chroma := range 5 {
+		for lightness := range 21 {
+			for hue := range 80 {
+				c := color.LCH(color.Value(lightness)*0.05, color.Value(chroma)*0.05, color.Value(hue)*4.5)
+				c.Print("█")
+			}
 
-		value.Fprint(io.Discard, name)
-		value.Print(name)
-		value.Println(name)
+			fmt.Println()
+		}
+
+		fmt.Println()
 	}
 }
+
+func testRGBColors(t *testing.T) {
+	rgbColors := map[string]color.Color{
+		"RGB.black": color.RGB(0.0, 0.0, 0.0),
+		"RGB.white": color.RGB(1.0, 1.0, 1.0),
+		"RGB.red":   color.RGB(1.0, 0.0, 0.0),
+		"RGB.green": color.RGB(0.0, 1.0, 0.0),
+		"RGB.blue":  color.RGB(0.0, 0.0, 1.0),
+	}
+
+	for name, c := range rgbColors {
+		testColor(t, c, name)
+	}
+}
+
+func testLCHColors(t *testing.T) {
+	lchColors := map[string]color.Color{
+		"LCH.black": color.LCH(0.0, 0.0, 0.0),
+		"LCH.white": color.LCH(1.0, 0.0, 0.0),
+		"LCH.red":   color.LCH(0.6, 0.5, 20.0),
+		"LCH.green": color.LCH(0.6, 0.5, 161.0),
+		"LCH.blue":  color.LCH(0.6, 0.5, 240.0),
+	}
+
+	for name, c := range lchColors {
+		testColor(t, c, name)
+	}
+}
+
+func testColor(t *testing.T, c color.Color, name string) {
+	assert.True(t, c.R >= 0.0)
+	assert.True(t, c.G >= 0.0)
+	assert.True(t, c.B >= 0.0)
+
+	assert.True(t, c.R <= 1.0)
+	assert.True(t, c.G <= 1.0)
+	assert.True(t, c.B <= 1.0)
+
+	c.Fprint(io.Discard, name)
+	c.Print(name)
+	c.Println(name)
+}

LCH.go

@@ -0,0 +1,56 @@
+package color
+
+import (
+	"math"
+)
+
+// LCH represents a color using lightness, chroma and hue (oklch).
+func LCH(lightness Value, chroma Value, hue Value) Color {
+	hue *= math.Pi / 180.0
+	a := chroma * math.Cos(hue)
+	b := chroma * math.Sin(hue)
+
+	r, g, b := labToRGB(lightness, a, b)
+
+	r = gammaCorrection(r)
+	g = gammaCorrection(g)
+	b = gammaCorrection(b)
+
+	return Color{r, g, b}
+}
+
+// LAB to linear sRGB
+// Source: https://bottosson.github.io/posts/oklab/
+func labToRGB(lightness Value, a Value, b Value) (Value, Value, Value) {
+	l := lightness + 0.3963377773761749*a + 0.21580375730991364*b
+	m := lightness - 0.10556134581565857*a - 0.0638541728258133*b
+	s := lightness - 0.08948418498039246*a - 1.2914855480194092*b
+
+	l = l * l * l
+	m = m * m * m
+	s = s * s * s
+
+	red := 4.0767416621*l - 3.3077115913*m + 0.2309699292*s
+	green := -1.2684380046*l + 2.6097574011*m - 0.3413193965*s
+	blue := -0.0041960863*l - 0.7034186147*m + 1.7076147010*s
+
+	return red, green, blue
+}
+
+// Gamma correction
+// Source: IEC 61966-2-2
+func gammaCorrection(x Value) Value {
+	if x < 0 {
+		return 0
+	}
+
+	if x <= 0.0031308 {
+		return 12.92 * x
+	}
+
+	if x < 1.0 {
+		return 1.055*math.Pow(x, 1/2.4) - 0.055
+	}
+
+	return 1.0
+}

README.md

@@ -4,7 +4,9 @@ Adds color to your terminal output.
 
 ## Features
 
-- Truecolor output
+- RGB color space
+- OKLCH color space
+- Truecolor terminal output
 
 ## Installation
 
@@ -22,15 +24,19 @@ red.Println("red text")
 ## Tests
 
 ```
-PASS: TestColor
+PASS: TestNoColors
+PASS: TestColors
+PASS: TestRainbow
 coverage: 100.0% of statements
 ```
 
 ## Benchmarks
 
 ```
-BenchmarkRGB-12       	1000000000	         0.3139 ns/op       0 B/op       0 allocs/op
-BenchmarkFprint-12    	25758495	        45.38 ns/op	        0 B/op       0 allocs/op
+BenchmarkRGB-12                	1000000000	         0.3132 ns/op	   0 B/op	       0 allocs/op
+BenchmarkLCH-12                	11214220	       107.1 ns/op	       0 B/op	       0 allocs/op
+BenchmarkFprintColorized-12    	 6356535	       188.4 ns/op	       0 B/op	       0 allocs/op
+BenchmarkFprintRaw-12          	27374659	        43.76 ns/op	       0 B/op	       0 allocs/op
 ```
 
 ## License