tins2020/img/color.go
Sander Schobers cd5ca3f04f Added tool to color image.
Separated some image related methods.
Added feedback for simulation speed (colored buttons).
2020-05-10 17:40:56 +02:00

63 lines
1.2 KiB
Go

package img
import (
"errors"
"image/color"
"regexp"
)
var hexColorRE = regexp.MustCompile(`^#?([0-9A-Fa-f]{2})-?([0-9A-Fa-f]{2})-?([0-9A-Fa-f]{2})-?([0-9A-Fa-f]{2})?$`)
func HexColor(s string) (color.RGBA, error) {
match := hexColorRE.FindStringSubmatch(s)
if match == nil {
return color.RGBA{}, errors.New("invalid color format")
}
values, err := HexToInts(match[1:]...)
if err != nil {
return color.RGBA{}, err
}
a := 255
if len(match[4]) > 0 {
a = values[3]
}
return color.RGBA{R: uint8(values[0]), G: uint8(values[1]), B: uint8(values[2]), A: uint8(a)}, nil
}
func MustHexColor(s string) color.RGBA {
color, err := HexColor(s)
if err != nil {
panic(err)
}
return color
}
func HexToInt(s string) (int, error) {
var i int
for _, c := range s {
i *= 16
if c >= '0' && c <= '9' {
i += int(c - '0')
} else if c >= 'A' && c <= 'F' {
i += int(c - 'A' + 10)
} else if c >= 'a' && c <= 'f' {
i += int(c - 'a' + 10)
} else {
return 0, errors.New("hex digit not supported")
}
}
return i, nil
}
func HexToInts(s ...string) ([]int, error) {
ints := make([]int, len(s))
for i, s := range s {
value, err := HexToInt(s)
if err != nil {
return nil, err
}
ints[i] = value
}
return ints, nil
}