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tomo-old/artist/line.go
2023-01-24 16:41:12 -05:00

144 lines
2.7 KiB
Go

package artist
import "image"
import "image/color"
import "git.tebibyte.media/sashakoshka/tomo"
// TODO: draw thick lines more efficiently
// Line draws a line from one point to another with the specified weight and
// pattern.
func Line (
destination tomo.Canvas,
source Pattern,
weight int,
min image.Point,
max image.Point,
) (
updatedRegion image.Rectangle,
) {
updatedRegion = image.Rectangle { Min: min, Max: max }.Canon()
updatedRegion.Max.X ++
updatedRegion.Max.Y ++
width := updatedRegion.Dx()
height := updatedRegion.Dy()
if abs(max.Y - min.Y) <
abs(max.X - min.X) {
if max.X < min.X {
temp := min
min = max
max = temp
}
lineLow(destination, source, weight, min, max, width, height)
} else {
if max.Y < min.Y {
temp := min
min = max
max = temp
}
lineHigh(destination, source, weight, min, max, width, height)
}
return
}
func lineLow (
destination tomo.Canvas,
source Pattern,
weight int,
min image.Point,
max image.Point,
width, height int,
) {
data, stride := destination.Buffer()
bounds := destination.Bounds()
deltaX := max.X - min.X
deltaY := max.Y - min.Y
yi := 1
if deltaY < 0 {
yi = -1
deltaY *= -1
}
D := (2 * deltaY) - deltaX
y := min.Y
for x := min.X; x < max.X; x ++ {
if !(image.Point { x, y }).In(bounds) { break }
squareAround(data, stride, source, x, y, width, height, weight)
// data[x + y * stride] = source.AtWhen(x, y, width, height)
if D > 0 {
y += yi
D += 2 * (deltaY - deltaX)
} else {
D += 2 * deltaY
}
}
}
func lineHigh (
destination tomo.Canvas,
source Pattern,
weight int,
min image.Point,
max image.Point,
width, height int,
) {
data, stride := destination.Buffer()
bounds := destination.Bounds()
deltaX := max.X - min.X
deltaY := max.Y - min.Y
xi := 1
if deltaX < 0 {
xi = -1
deltaX *= -1
}
D := (2 * deltaX) - deltaY
x := min.X
for y := min.Y; y < max.Y; y ++ {
if !(image.Point { x, y }).In(bounds) { break }
squareAround(data, stride, source, x, y, width, height, weight)
// data[x + y * stride] = source.AtWhen(x, y, width, height)
if D > 0 {
x += xi
D += 2 * (deltaX - deltaY)
} else {
D += 2 * deltaX
}
}
}
func abs (in int) (out int) {
if in < 0 { in *= -1}
out = in
return
}
// TODO: this method of doing things sucks and can cause a segfault. we should
// not be doing it this way
func squareAround (
data []color.RGBA,
stride int,
source Pattern,
x, y, patternWidth, patternHeight, diameter int,
) {
minY := y - diameter + 1
minX := x - diameter + 1
maxY := y + diameter
maxX := x + diameter
for y = minY; y < maxY; y ++ {
for x = minX; x < maxX; x ++ {
data[x + y * stride] =
source.AtWhen(x, y, patternWidth, patternHeight)
}}
}