121 lines
2.1 KiB
Go
121 lines
2.1 KiB
Go
package artist
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import "image"
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import "git.tebibyte.media/sashakoshka/tomo"
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// Line draws a line from one point to another with the specified weight and
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// pattern.
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func Line (
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destination tomo.Canvas,
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source Pattern,
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weight int,
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min image.Point,
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max image.Point,
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) (
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updatedRegion image.Rectangle,
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) {
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// TODO: respect weight
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updatedRegion = image.Rectangle { Min: min, Max: max }.Canon()
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updatedRegion.Max.X ++
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updatedRegion.Max.Y ++
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width := updatedRegion.Dx()
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height := updatedRegion.Dy()
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if abs(max.Y - min.Y) <
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abs(max.X - min.X) {
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if max.X < min.X {
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temp := min
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min = max
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max = temp
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}
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lineLow(destination, source, weight, min, max, width, height)
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} else {
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if max.Y < min.Y {
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temp := min
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min = max
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max = temp
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}
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lineHigh(destination, source, weight, min, max, width, height)
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}
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return
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}
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func lineLow (
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destination tomo.Canvas,
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source Pattern,
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weight int,
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min image.Point,
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max image.Point,
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width, height int,
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) {
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data, stride := destination.Buffer()
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bounds := destination.Bounds()
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deltaX := max.X - min.X
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deltaY := max.Y - min.Y
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yi := 1
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if deltaY < 0 {
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yi = -1
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deltaY *= -1
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}
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D := (2 * deltaY) - deltaX
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y := min.Y
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for x := min.X; x < max.X; x ++ {
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if !(image.Point { x, y }).In(bounds) { break }
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data[x + y * stride] = source.AtWhen(x, y, width, height)
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if D > 0 {
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y += yi
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D += 2 * (deltaY - deltaX)
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} else {
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D += 2 * deltaY
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}
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}
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}
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func lineHigh (
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destination tomo.Canvas,
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source Pattern,
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weight int,
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min image.Point,
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max image.Point,
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width, height int,
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) {
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data, stride := destination.Buffer()
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bounds := destination.Bounds()
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deltaX := max.X - min.X
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deltaY := max.Y - min.Y
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xi := 1
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if deltaX < 0 {
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xi = -1
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deltaX *= -1
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}
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D := (2 * deltaX) - deltaY
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x := min.X
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for y := min.Y; y < max.Y; y ++ {
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if !(image.Point { x, y }).In(bounds) { break }
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data[x + y * stride] = source.AtWhen(x, y, width, height)
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if D > 0 {
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x += xi
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D += 2 * (deltaX - deltaY)
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} else {
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D += 2 * deltaX
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}
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}
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}
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func abs (in int) (out int) {
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if in < 0 { in *= -1}
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out = in
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return
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}
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