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tomo-old/artist/checkered.go
2023-01-24 14:08:47 -05:00

52 lines
1.2 KiB
Go

package artist
import "image/color"
// Checkered is a pattern that produces a grid of two alternating colors.
type Checkered struct {
First Pattern
Second Pattern
CellWidth, CellHeight int
}
// AtWhen satisfies the Pattern interface.
func (pattern Checkered) AtWhen (x, y, width, height int) (c color.RGBA) {
twidth := pattern.CellWidth * 2
theight := pattern.CellHeight * 2
x %= twidth
y %= theight
if x < 0 { x += twidth }
if y < 0 { x += theight }
n := 0
if x >= pattern.CellWidth { n ++ }
if y >= pattern.CellHeight { n ++ }
x %= pattern.CellWidth
y %= pattern.CellHeight
if n % 2 == 0 {
return pattern.First.AtWhen (
x, y, pattern.CellWidth, pattern.CellHeight)
} else {
return pattern.Second.AtWhen (
x, y, pattern.CellWidth, pattern.CellHeight)
}
}
// Tiled is a pattern that tiles another pattern accross a grid.
type Tiled struct {
Pattern
CellWidth, CellHeight int
}
// AtWhen satisfies the Pattern interface.
func (pattern Tiled) AtWhen (x, y, width, height int) (c color.RGBA) {
x %= pattern.CellWidth
y %= pattern.CellHeight
if x < 0 { x += pattern.CellWidth }
if y < 0 { y += pattern.CellHeight }
return pattern.Pattern.AtWhen (
x, y, pattern.CellWidth, pattern.CellHeight)
}