1package ansi
2
3import (
4 "fmt"
5 "image/color"
6 "strconv"
7 "strings"
8
9 "github.com/lucasb-eyer/go-colorful"
10)
11
12// colorToHexString returns a hex string representation of a color.
13func colorToHexString(c color.Color) string { //nolint:unused
14 if c == nil {
15 return ""
16 }
17 shift := func(v uint32) uint32 {
18 if v > 0xff {
19 return v >> 8
20 }
21 return v
22 }
23 r, g, b, _ := c.RGBA()
24 r, g, b = shift(r), shift(g), shift(b)
25 return fmt.Sprintf("#%02x%02x%02x", r, g, b)
26}
27
28// rgbToHex converts red, green, and blue values to a hexadecimal value.
29//
30// hex := rgbToHex(0, 0, 255) // 0x0000FF
31func rgbToHex(r, g, b uint32) uint32 { //nolint:unused
32 return r<<16 + g<<8 + b
33}
34
35type shiftable interface {
36 ~uint | ~uint16 | ~uint32 | ~uint64
37}
38
39func shift[T shiftable](x T) T {
40 if x > 0xff {
41 x >>= 8
42 }
43 return x
44}
45
46// XParseColor is a helper function that parses a string into a color.Color. It
47// provides a similar interface to the XParseColor function in Xlib. It
48// supports the following formats:
49//
50// - #RGB
51// - #RRGGBB
52// - rgb:RRRR/GGGG/BBBB
53// - rgba:RRRR/GGGG/BBBB/AAAA
54//
55// If the string is not a valid color, nil is returned.
56//
57// See: https://linux.die.net/man/3/xparsecolor
58func XParseColor(s string) color.Color {
59 switch {
60 case strings.HasPrefix(s, "#"):
61 c, err := colorful.Hex(s)
62 if err != nil {
63 return nil
64 }
65
66 return c
67 case strings.HasPrefix(s, "rgb:"):
68 parts := strings.Split(s[4:], "/")
69 if len(parts) != 3 {
70 return nil
71 }
72
73 r, _ := strconv.ParseUint(parts[0], 16, 32)
74 g, _ := strconv.ParseUint(parts[1], 16, 32)
75 b, _ := strconv.ParseUint(parts[2], 16, 32)
76
77 return color.RGBA{uint8(shift(r)), uint8(shift(g)), uint8(shift(b)), 255} //nolint:gosec
78 case strings.HasPrefix(s, "rgba:"):
79 parts := strings.Split(s[5:], "/")
80 if len(parts) != 4 {
81 return nil
82 }
83
84 r, _ := strconv.ParseUint(parts[0], 16, 32)
85 g, _ := strconv.ParseUint(parts[1], 16, 32)
86 b, _ := strconv.ParseUint(parts[2], 16, 32)
87 a, _ := strconv.ParseUint(parts[3], 16, 32)
88
89 return color.RGBA{uint8(shift(r)), uint8(shift(g)), uint8(shift(b)), uint8(shift(a))} //nolint:gosec
90 }
91 return nil
92}
93
94type ordered interface {
95 ~int | ~int8 | ~int16 | ~int32 | ~int64 |
96 ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
97 ~float32 | ~float64 |
98 ~string
99}
100
101func max[T ordered](a, b T) T { //nolint:predeclared
102 if a > b {
103 return a
104 }
105 return b
106}