clifmt/colors.go

98 lines
2.0 KiB
Go

package clifmt
import (
"fmt"
"io"
"strconv"
)
type terminalColor uint32
type Theme map[string]terminalColor
var theme Theme = make(map[string]terminalColor)
func init() {
theme["black"] = 0x000000
theme["white"] = 0xffffff
theme["red"] = 0xff0000
theme["green"] = 0x00ff00
theme["blue"] = 0x0000ff
theme["yellow"] = 0xffff00
theme["orange"] = 0xff8c00
theme["purple"] = 0x800080
theme["navy"] = 0x000080
theme["aqua"] = 0x00ffff
theme["gray"] = 0x808080
theme["silver"] = 0xc0c0c0
theme["fuchsia"] = 0xff00ff
theme["olive"] = 0x808000
theme["teal"] = 0x008080
theme["brown"] = 0x800000
}
// fromName returns the integer value of a color name
// from the built-in color map ; it is case insensitive
func fromName(s string) (terminalColor, error) {
value, ok := theme[s]
if !ok {
return 0, fmt.Errorf("unknown color name '%s'", s)
}
return value, nil
}
// fromHex returns the integer value associated with
// an hexadecimal string (full-sized or short version)
// the format is 'abc' or 'abcdef'
func fromHex(s string) (terminalColor, error) {
if len(s) != 3 && len(s) != 6 {
return 0, fmt.Errorf("expect a size of 3 or 6 (remove the '#' prefix)")
}
// short version
input := s
if len(s) == 3 {
input = fmt.Sprintf("%c%c%c%c%c%c", s[0], s[0], s[1], s[1], s[2], s[2])
}
n, err := strconv.ParseUint(input, 16, 32)
if err != nil {
return 0, err
}
return terminalColor(n), nil
}
// parseColor tries to parse a color string (can be a name or an hexa value)
func parseColor(s string) (terminalColor, error) {
// (0) ...
if len(s) < 1 {
return 0, io.ErrUnexpectedEOF
}
// (1) hexa
if s[0] == '#' {
return fromHex(s[1:])
}
// (2) name
return fromName(s)
}
// Red component of the color
func (c terminalColor) Red() uint8 {
return uint8((c >> 16) & 0xff)
}
// Green component of the color
func (c terminalColor) Green() uint8 {
return uint8((c >> 8) & 0xff)
}
// Blue component of the color
func (c terminalColor) Blue() uint8 {
return uint8(c & 0xff)
}