126 lines
2.8 KiB
Go
126 lines
2.8 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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var lineSegments = func() map[[2]geo.XY]string {
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m := map[[2]geo.XY]string{
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{geo.Left, geo.Right}: "─",
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{geo.Down, geo.Up}: "│",
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{geo.Right, geo.Down}: "┌",
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{geo.Left, geo.Down}: "┐",
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{geo.Right, geo.Up}: "└",
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{geo.Left, geo.Up}: "┘",
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}
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// the inverse segments use the same characters
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for seg, str := range m {
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seg[0], seg[1] = seg[1], seg[0]
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m[seg] = str
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}
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return m
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}()
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var edgeSegments = map[geo.XY]string{
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geo.Up: "┴",
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geo.Down: "┬",
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geo.Left: "┤",
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geo.Right: "├",
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}
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// actual unicode arrows were fucking up my terminal, and they didn't even
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// connect properly with the line segments anyway
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var arrows = map[geo.XY]string{
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geo.Up: "^",
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geo.Down: "v",
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geo.Left: "<",
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geo.Right: ">",
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}
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type line [2]*box
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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 (l line) secondaryDir(primary geo.XY) geo.XY {
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fromRect, toRect := l[0].rect(), l[1].rect()
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rels := make([]int, len(geo.Units))
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for i, dir := range geo.Units {
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rels[i] = toRect.Edge(dir.Inv()) - fromRect.Edge(dir)
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if dir == geo.Up || dir == geo.Left {
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rels[i] *= -1
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}
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}
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var secondary geo.XY
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var secondaryMax int
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var secondarySet bool
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for i, rel := range rels {
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if geo.Units[i] == primary {
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continue
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} else if geo.Units[i][0] == 0 && primary[0] == 0 {
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continue
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} else if geo.Units[i][1] == 0 && primary[1] == 0 {
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continue
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} else if !secondarySet || rel > secondaryMax {
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secondary = geo.Units[i]
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secondaryMax = rel
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secondarySet = true
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}
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}
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return secondary
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}
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func (l line) draw(term *terminal.Terminal, dir geo.XY) {
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from, to := *l[0], *l[1]
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dirSec := l.secondaryDir(dir)
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dirInv := dir.Inv()
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start := from.rect().EdgeMidpoint(dir, rounder)
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end := to.rect().EdgeMidpoint(dirInv, rounder)
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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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var pts []geo.XY
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midPrim := along(mid, dir)
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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, dir); 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(dir)
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}
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for i, pt := range pts {
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var str string
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switch {
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case i == 0:
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str = edgeSegments[dir]
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case i == len(pts)-1:
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str = arrows[dir]
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default:
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prev, next := pts[i-1], pts[i+1]
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seg := [2]geo.XY{
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prev.Sub(pt),
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next.Sub(pt),
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}
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str = lineSegments[seg]
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}
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term.MoveCursorTo(pt)
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term.Printf(str)
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}
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}
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