Update doc

README.md

@@ -1,34 +1,33 @@
-# CSS Color Parser
+# Golang CSS Color Parser Library
 
 [![PkgGoDev](https://pkg.go.dev/badge/github.com/mazznoer/csscolorparser)](https://pkg.go.dev/github.com/mazznoer/csscolorparser)
 [![Build Status](https://travis-ci.org/mazznoer/csscolorparser.svg?branch=master)](https://travis-ci.org/mazznoer/csscolorparser)
 [![Build Status](https://github.com/mazznoer/csscolorparser/workflows/Go/badge.svg)](https://github.com/mazznoer/csscolorparser/actions)
 [![go report](https://goreportcard.com/badge/github.com/mazznoer/csscolorparser)](https://goreportcard.com/report/github.com/mazznoer/csscolorparser)
 [![codecov](https://codecov.io/gh/mazznoer/csscolorparser/branch/master/graph/badge.svg)](https://codecov.io/gh/mazznoer/csscolorparser)
+[![Lines of Code](https://tokei.rs/b1/github/mazznoer/csscolorparser?category=code)](https://github.com/mazznoer/csscolorparser)
 
-Go (Golang) CSS color parser.
+[Go](https://www.golang.org/) library for parsing CSS color string as defined in the W3C's [CSS Color Module Level 4](https://www.w3.org/TR/css-color-4/).
 
-It support W3C's CSS color module level 4.
+## Supported Color Format
 
-```go
-import "github.com/mazznoer/csscolorparser"
-```
+* [Named colors](https://www.w3.org/TR/css-color-4/#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()`
+* `hwba()`, `hsv()`, `hsva()` - not in CSS standard.
 
-## Usage
+Not yet supported: `lab()`, `lch()`.
 
-```go
-c, err := csscolorparser.Parse("gold")
-
-if err != nil {
-	panic(err)
-}
-```
-
-## Supported Format
-
-It support named colors, hexadecimal (`#rgb`, `#rgba`, `#rrggbb`, `#rrggbbaa`), `rgb()`, `rgba()`, `hsl()`, `hsla()`, `hwb()`, and `hsv()`.
+### Example Color Format
 
 ```
+transparent
 lime
 #0f0
 #0f0f
@@ -52,6 +51,32 @@ hsv(120,100%,100%)
 hsv(120deg 100% 100% / 100%)
 ```
 
+## Usage Examples
+
+```go
+import "github.com/mazznoer/csscolorparser"
+```
+
+```go
+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
 
-[Go Playground](https://play.golang.org/p/7kb62KSARwa)
+* [Playground 1](https://play.golang.org/p/8KMIc1TLQB0)
+* [Playground 2](https://play.golang.org/p/7kb62KSARwa)
+
+## Similar Projects
+
+* [csscolorparser](https://github.com/mazznoer/csscolorparser-rs) (Rust)
+* [csscolorparser](https://github.com/deanm/css-color-parser-js) (Javascript)
+

colorparser.go

@@ -1,3 +1,4 @@
+// Package csscolorparser provides function for parsing CSS color string as defined in the W3C's CSS color module level 4.
 package csscolorparser
 
 import (
@@ -9,10 +10,12 @@ import (
 
 // Inspired by https://github.com/deanm/css-color-parser-js
 
+// R, G, B, A values in the range 0..1
 type Color struct {
 	R, G, B, A float64
 }
 
+// Implement the Go color.Color interface.
 func (c Color) RGBA() (r, g, b, a uint32) {
 	r = uint32(math.Round(c.R * 65535))
 	g = uint32(math.Round(c.G * 65535))
@@ -21,6 +24,7 @@ func (c Color) RGBA() (r, g, b, a uint32) {
 	return
 }
 
+// RGBA255 returns R, G, B, A values in the range 0..255
 func (c Color) RGBA255() (r, g, b, a uint8) {
 	r = uint8(math.Round(c.R * 255))
 	g = uint8(math.Round(c.G * 255))
@@ -29,6 +33,7 @@ func (c Color) RGBA255() (r, g, b, a uint8) {
 	return
 }
 
+// HexString returns CSS hexadecimal string.
 func (c Color) HexString() string {
 	r, g, b, a := c.RGBA255()
 	if a < 255 {
@@ -37,12 +42,13 @@ func (c Color) HexString() string {
 	return fmt.Sprintf("#%02x%02x%02x", r, g, b)
 }
 
+// RGBString returns CSS RGB string.
 func (c Color) RGBString() string {
 	r, g, b, _ := c.RGBA255()
 	if c.A < 1 {
-		return fmt.Sprintf("rgba(%v,%v,%v,%v)", r, g, b, c.A)
+		return fmt.Sprintf("rgba(%d,%d,%d,%v)", r, g, b, c.A)
 	}
-	return fmt.Sprintf("rgb(%v,%v,%v)", r, g, b)
+	return fmt.Sprintf("rgb(%d,%d,%d)", r, g, b)
 }
 
 var black = Color{0, 0, 0, 1}

example_test.go

@@ -0,0 +1,43 @@
+package csscolorparser_test
+
+import (
+	"fmt"
+
+	"github.com/mazznoer/csscolorparser"
+)
+
+func Example_namedColor() {
+	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)
+}
+
+func Example_rgbColor() {
+	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)
+}