This repository has been archived on 2023-08-08. You can view files and clone it, but cannot push or open issues or pull requests.
tomo-old/artist/gradient.go

46 lines
1.4 KiB
Go
Raw Normal View History

package artist
import "image/color"
// Gradient is a pattern that interpolates between two colors.
type Gradient struct {
First Pattern
Second Pattern
Orientation
}
// AtWhen satisfies the Pattern interface.
func (pattern Gradient) AtWhen (x, y, width, height int) (c color.RGBA) {
var position float64
switch pattern.Orientation {
case OrientationVertical:
2023-01-24 14:02:35 -07:00
position = float64(y) / float64(height)
case OrientationDiagonalRight:
2023-01-24 14:02:35 -07:00
position = (float64(width - x) / float64(width) +
float64(y) / float64(height)) / 2
case OrientationHorizontal:
2023-01-24 14:02:35 -07:00
position = float64(x) / float64(width)
case OrientationDiagonalLeft:
2023-01-24 14:02:35 -07:00
position = (float64(x) / float64(width) +
float64(y) / float64(height)) / 2
}
firstColor := pattern.First.AtWhen(x, y, width, height)
secondColor := pattern.Second.AtWhen(x, y, width, height)
return LerpRGBA(firstColor, secondColor, position)
}
// Lerp linearally interpolates between two integer values.
func Lerp (first, second int, fac float64) (n int) {
return int(float64(first) * (1 - fac) + float64(second) * fac)
}
// LerpRGBA linearally interpolates between two color.RGBA values.
func LerpRGBA (first, second color.RGBA, fac float64) (c color.RGBA) {
return color.RGBA {
R: uint8(Lerp(int(first.R), int(second.R), fac)),
G: uint8(Lerp(int(first.G), int(second.G), fac)),
B: uint8(Lerp(int(first.G), int(second.B), fac)),
}
}