44 lines
755 B
Go
44 lines
755 B
Go
|
package captcha
|
||
|
|
|
||
|
|
import "math"
|
||
|
|
|
||
|
|
type hsva struct {
|
||
|
|
h, s, v float64
|
||
|
|
a uint8
|
||
|
|
}
|
||
|
|
|
||
|
|
// https://gist.github.com/mjackson/5311256
|
||
|
|
func (c hsva) RGBA() (r, g, b, a uint32) {
|
||
|
|
var i = math.Floor(c.h * 6)
|
||
|
|
var f = c.h*6 - i
|
||
|
|
var p = c.v * (1.0 - c.s)
|
||
|
|
var q = c.v * (1.0 - f*c.s)
|
||
|
|
var t = c.v * (1 - (1-f)*c.s)
|
||
|
|
|
||
|
|
var red, green, blue float64
|
||
|
|
switch int(i) % 6 {
|
||
|
|
case 0:
|
||
|
|
red, green, blue = c.v, t, p
|
||
|
|
case 1:
|
||
|
|
red, green, blue = q, c.v, p
|
||
|
|
case 2:
|
||
|
|
red, green, blue = p, c.v, t
|
||
|
|
case 3:
|
||
|
|
red, green, blue = p, q, c.v
|
||
|
|
case 4:
|
||
|
|
red, green, blue = t, p, c.v
|
||
|
|
case 5:
|
||
|
|
red, green, blue = c.v, p, q
|
||
|
|
}
|
||
|
|
|
||
|
|
r = uint32(red * 255)
|
||
|
|
r |= r << 8
|
||
|
|
g = uint32(green * 255)
|
||
|
|
g |= g << 8
|
||
|
|
b = uint32(blue * 255)
|
||
|
|
b |= b << 8
|
||
|
|
a = uint32(c.a)
|
||
|
|
a |= a << 8
|
||
|
|
return
|
||
|
|
}
|