Noah Petherbridge
2b42a072a0
* All private Doodle source code into the pkg/ folder. * Potentially public code into the lib/ folder. * Centralize the logger into a subpackage.
44 lines
764 B
Go
44 lines
764 B
Go
package draw
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import (
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"math"
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"git.kirsle.net/apps/doodle/lib/render"
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)
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// Line is a generator that returns the X,Y coordinates to draw a line.
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// https://en.wikipedia.org/wiki/Digital_differential_analyzer_(graphics_algorithm)
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func Line(x1, y1, x2, y2 int32) chan render.Point {
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generator := make(chan render.Point)
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go func() {
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var (
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dx = float64(x2 - x1)
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dy = float64(y2 - y1)
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)
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var step float64
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if math.Abs(dx) >= math.Abs(dy) {
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step = math.Abs(dx)
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} else {
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step = math.Abs(dy)
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}
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dx = dx / step
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dy = dy / step
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x := float64(x1)
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y := float64(y1)
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for i := 0; i <= int(step); i++ {
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generator <- render.Point{
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X: int32(x),
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Y: int32(y),
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}
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x += dx
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y += dy
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}
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close(generator)
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}()
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return generator
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}
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