package main
// This program generates palette.go. Invoke it as
-// go run gen.go | gofmt > palette.go
+// go run gen.go -output palette.go
import (
+ "bytes"
+ "flag"
"fmt"
+ "go/format"
+ "io"
+ "io/ioutil"
+ "log"
)
+var filename = flag.String("output", "palette.go", "output file name")
+
func main() {
- fmt.Println(`// Copyright 2013 The Go Authors. All rights reserved.
+ flag.Parse()
+
+ var buf bytes.Buffer
+
+ fmt.Fprintln(&buf, `// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.`)
- fmt.Println()
- fmt.Println("// generated by go run gen.go; DO NOT EDIT")
- fmt.Println()
- fmt.Println("// Package palette provides standard color palettes.")
- fmt.Println("package palette")
- fmt.Println()
- fmt.Println(`import "image/color"`)
- fmt.Println()
- printPlan9()
- printWebSafe()
+ fmt.Fprintln(&buf)
+ fmt.Fprintln(&buf, "// generated by go run gen.go -output palette.go; DO NOT EDIT")
+ fmt.Fprintln(&buf)
+ fmt.Fprintln(&buf, "package palette")
+ fmt.Fprintln(&buf)
+ fmt.Fprintln(&buf, `import "image/color"`)
+ fmt.Fprintln(&buf)
+ printPlan9(&buf)
+ printWebSafe(&buf)
+
+ data, err := format.Source(buf.Bytes())
+ if err != nil {
+ log.Fatal(err)
+ }
+ err = ioutil.WriteFile(*filename, data, 0644)
+ if err != nil {
+ log.Fatal(err)
+ }
}
-func printPlan9() {
+func printPlan9(w io.Writer) {
c, lines := [3]int{}, [256]string{}
for r, i := 0, 0; r != 4; r++ {
for v := 0; v != 4; v, i = v+1, i+16 {
}
}
}
- fmt.Println("// Plan9 is a 256-color palette that partitions the 24-bit RGB space")
- fmt.Println("// into 4×4×4 subdivision, with 4 shades in each subcube. Compared to the")
- fmt.Println("// WebSafe, the idea is to reduce the color resolution by dicing the")
- fmt.Println("// color cube into fewer cells, and to use the extra space to increase the")
- fmt.Println("// intensity resolution. This results in 16 gray shades (4 gray subcubes with")
- fmt.Println("// 4 samples in each), 13 shades of each primary and secondary color (3")
- fmt.Println("// subcubes with 4 samples plus black) and a reasonable selection of colors")
- fmt.Println("// covering the rest of the color cube. The advantage is better representation")
- fmt.Println("// of continuous tones.")
- fmt.Println("//")
- fmt.Println("// This palette was used in the Plan 9 Operating System, described at")
- fmt.Println("// http://plan9.bell-labs.com/magic/man2html/6/color")
- fmt.Println("var Plan9 = []color.Color{")
+ fmt.Fprintln(w, "// Plan9 is a 256-color palette that partitions the 24-bit RGB space")
+ fmt.Fprintln(w, "// into 4×4×4 subdivision, with 4 shades in each subcube. Compared to the")
+ fmt.Fprintln(w, "// WebSafe, the idea is to reduce the color resolution by dicing the")
+ fmt.Fprintln(w, "// color cube into fewer cells, and to use the extra space to increase the")
+ fmt.Fprintln(w, "// intensity resolution. This results in 16 gray shades (4 gray subcubes with")
+ fmt.Fprintln(w, "// 4 samples in each), 13 shades of each primary and secondary color (3")
+ fmt.Fprintln(w, "// subcubes with 4 samples plus black) and a reasonable selection of colors")
+ fmt.Fprintln(w, "// covering the rest of the color cube. The advantage is better representation")
+ fmt.Fprintln(w, "// of continuous tones.")
+ fmt.Fprintln(w, "//")
+ fmt.Fprintln(w, "// This palette was used in the Plan 9 Operating System, described at")
+ fmt.Fprintln(w, "// http://plan9.bell-labs.com/magic/man2html/6/color")
+ fmt.Fprintln(w, "var Plan9 = []color.Color{")
for _, line := range lines {
- fmt.Println(line)
+ fmt.Fprintln(w, line)
}
- fmt.Println("}")
- fmt.Println()
+ fmt.Fprintln(w, "}")
+ fmt.Fprintln(w)
}
-func printWebSafe() {
+func printWebSafe(w io.Writer) {
lines := [6 * 6 * 6]string{}
for r := 0; r < 6; r++ {
for g := 0; g < 6; g++ {
}
}
}
- fmt.Println("// WebSafe is a 216-color palette that was popularized by early versions")
- fmt.Println("// of Netscape Navigator. It is also known as the Netscape Color Cube.")
- fmt.Println("//")
- fmt.Println("// See http://en.wikipedia.org/wiki/Web_colors#Web-safe_colors for details.")
- fmt.Println("var WebSafe = []color.Color{")
+ fmt.Fprintln(w, "// WebSafe is a 216-color palette that was popularized by early versions")
+ fmt.Fprintln(w, "// of Netscape Navigator. It is also known as the Netscape Color Cube.")
+ fmt.Fprintln(w, "//")
+ fmt.Fprintln(w, "// See http://en.wikipedia.org/wiki/Web_colors#Web-safe_colors for details.")
+ fmt.Fprintln(w, "var WebSafe = []color.Color{")
for _, line := range lines {
- fmt.Println(line)
+ fmt.Fprintln(w, line)
}
- fmt.Println("}")
- fmt.Println()
+ fmt.Fprintln(w, "}")
+ fmt.Fprintln(w)
}