76 lines
1.9 KiB
Go
76 lines
1.9 KiB
Go
package main
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import (
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"github.com/mediocregopher/ginger/gim/geo"
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"github.com/mediocregopher/ginger/gim/terminal"
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)
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type line struct {
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from, to *box
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fromI, toI int
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body string
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}
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// given the "primary" direction the line should be headed, picks a possible
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// secondary one which may be used to detour along the path in order to reach
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// the destination (in the case that the two boxes are diagonal from each other)
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func secondaryDir(flowDir, start, end geo.XY) geo.XY {
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var perpDir geo.XY
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perpDir[0], perpDir[1] = flowDir[1], flowDir[0]
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return end.Sub(start).Mul(perpDir.Abs()).Unit()
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}
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func (l line) draw(buf *terminal.Buffer, flowDir, secFlowDir geo.XY) {
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from, to := *(l.from), *(l.to)
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start := from.rect().Edge(flowDir, secFlowDir)[0].Add(secFlowDir.Scale(l.fromI*2 + 1))
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end := to.rect().Edge(flowDir.Inv(), secFlowDir)[0].Add(secFlowDir.Scale(l.toI*2 + 1))
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dirSec := secondaryDir(flowDir, start, end)
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mid := start.Midpoint(end, rounder)
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along := func(xy, dir geo.XY) int {
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if dir[0] != 0 {
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return xy[0]
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}
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return xy[1]
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}
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// collect the points along the line into an array
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var pts []geo.XY
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midPrim := along(mid, flowDir)
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endSec := along(end, dirSec)
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for curr := start; curr != end; {
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pts = append(pts, curr)
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if prim := along(curr, flowDir); prim == midPrim {
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if sec := along(curr, dirSec); sec != endSec {
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curr = curr.Add(dirSec)
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continue
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}
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}
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curr = curr.Add(flowDir)
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}
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// draw each point
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for i, pt := range pts {
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var r rune
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switch {
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case i == 0:
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r = terminal.SingleLine.Perpendicular(flowDir)
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case i == len(pts)-1:
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r = terminal.SingleLine.Arrow(flowDir)
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default:
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prev, next := pts[i-1], pts[i+1]
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r = terminal.SingleLine.Segment(prev.Sub(pt), next.Sub(pt))
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}
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buf.SetPos(pt)
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buf.WriteRune(r)
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}
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// draw the body
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if l.body != "" {
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bodyPos := mid.Add(geo.Left.Scale(len(l.body) / 2))
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buf.SetPos(bodyPos)
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buf.WriteString(l.body)
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}
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}
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