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package randomcolor
import (
"image/color"
"math/rand"
)
// Luminosity stores the level of luminosity for the generated color.
type Luminosity int
const (
// LIGHT is used to generate light colors
LIGHT Luminosity = iota
// DARK is used to generate dark colors
DARK
// BRIGHT is used to generator bright colors
BRIGHT
// RANDOM is used to generate colors of random luminosity
RANDOM
)
// New returns a random color in the specified hue and luminosity.
func New(hue Color, lum Luminosity) color.Color {
c := HSV{}
c.H = setHue(hue)
c.S = setSaturation(c, hue, lum)
c.V = setBrightness(c, lum)
if c.H == 0 {
c.H = 1
}
if c.H == 360 {
c.H = 359
}
// Rebase the h,s,v values
c.H = c.H / 360
c.S = c.S / 100
c.V = c.V / 100
return c
}
// Range represents a range between lower (Range[0]) and upper bounds (Range[1]).
type Range [2]int
// Color represents a color in a specified range
type Color struct {
HueRange Range
LowerBounds []Range
}
// SaturationRange returns the minimum and maximum saturation for the color.
func (c Color) SaturationRange() Range {
sMin := c.LowerBounds[0][0]
sMax := c.LowerBounds[len(c.LowerBounds)-1][0]
return Range{sMin, sMax}
}
// BrightnessRange returns the minimum and maximum brigthness for the color.
func (c Color) BrightnessRange() Range {
bMin := c.LowerBounds[len(c.LowerBounds)-1][1]
bMax := c.LowerBounds[0][1]
return Range{bMin, bMax}
}
func setHue(c Color) float64 {
hue := randWithin(c.HueRange[0], c.HueRange[1])
if hue < 0 {
hue = 360 + hue
}
return float64(hue)
}
func setSaturation(hsv HSV, hue Color, lum Luminosity) float64 {
if hue.HueRange == Monochrome.HueRange {
return 0
}
saturationRange := ColorInfo(int(hsv.H)).SaturationRange()
var sMin = saturationRange[0]
var sMax = saturationRange[1]
switch lum {
case BRIGHT:
sMin = 55
case DARK:
sMin = sMax - 10
case LIGHT:
sMax = 55
case RANDOM:
return float64(randWithin(0, 100))
}
return float64(randWithin(sMin, sMax))
}
func setBrightness(hsv HSV, lum Luminosity) float64 {
bMin := getMinimumBrightness(hsv)
bMax := 100
switch lum {
case DARK:
bMax = bMin + 20
case LIGHT:
bMin = (bMax + bMin) / 2
case BRIGHT:
//
default:
bMin = 0
bMax = 100
}
return float64(randWithin(bMin, bMax))
}
func getMinimumBrightness(hsv HSV) int {
var lowerBounds []Range
lowerBounds = ColorInfo(int(hsv.H)).LowerBounds
for i := 0; i < (len(lowerBounds) - 1); i++ {
s1 := float64(lowerBounds[i][0])
v1 := float64(lowerBounds[i][1])
s2 := float64(lowerBounds[i+1][0])
v2 := float64(lowerBounds[i+1][1])
if hsv.S >= s1 && hsv.S <= s2 {
m := (v2 - v1) / (s2 - s1)
b := v1 - m*s1
return int(m*hsv.S + b)
}
}
return 0
}
func randWithin(first, last int) int {
return first + rand.Intn(last+1-first)
}
|
