ginger/gim/line.go

114 lines
2.6 KiB
Go
Raw Normal View History

package main
import (
"github.com/mediocregopher/ginger/gim/geo"
"github.com/mediocregopher/ginger/gim/terminal"
)
var lineSegments = func() map[[2]geo.XY]string {
m := map[[2]geo.XY]string{
{geo.Left, geo.Right}: "─",
{geo.Down, geo.Up}: "│",
{geo.Right, geo.Down}: "┌",
{geo.Left, geo.Down}: "┐",
{geo.Right, geo.Up}: "└",
{geo.Left, geo.Up}: "┘",
}
// the inverse segments use the same characters
for seg, str := range m {
seg[0], seg[1] = seg[1], seg[0]
m[seg] = str
}
return m
}()
var edgeSegments = map[geo.XY]string{
geo.Up: "┴",
geo.Down: "┬",
geo.Left: "┤",
geo.Right: "├",
}
// actual unicode arrows were fucking up my terminal, and they didn't even
// connect properly with the line segments anyway
var arrows = map[geo.XY]string{
geo.Up: "^",
geo.Down: "v",
geo.Left: "<",
geo.Right: ">",
}
type line struct {
from, to *box
fromI, toI int
2018-06-02 04:35:12 +00:00
body string
}
// given the "primary" direction the line should be headed, picks a possible
// secondary one which may be used to detour along the path in order to reach
// the destination (in the case that the two boxes are diagonal from each other)
func secondaryDir(flowDir, start, end geo.XY) geo.XY {
var perpDir geo.XY
perpDir[0], perpDir[1] = flowDir[1], flowDir[0]
return end.Sub(start).Mul(perpDir.Abs()).Unit()
}
func (l line) draw(term *terminal.Terminal, flowDir, secFlowDir geo.XY) {
from, to := *(l.from), *(l.to)
start := from.rect().Edge(flowDir, secFlowDir)[0].Add(secFlowDir.Scale(l.fromI*2 + 1))
end := to.rect().Edge(flowDir.Inv(), secFlowDir)[0].Add(secFlowDir.Scale(l.toI*2 + 1))
dirSec := secondaryDir(flowDir, start, end)
mid := start.Midpoint(end, rounder)
along := func(xy, dir geo.XY) int {
if dir[0] != 0 {
return xy[0]
}
return xy[1]
}
2018-06-02 04:35:12 +00:00
// collect the points along the line into an array
var pts []geo.XY
midPrim := along(mid, flowDir)
endSec := along(end, dirSec)
for curr := start; curr != end; {
pts = append(pts, curr)
if prim := along(curr, flowDir); prim == midPrim {
if sec := along(curr, dirSec); sec != endSec {
curr = curr.Add(dirSec)
continue
}
}
curr = curr.Add(flowDir)
}
2018-06-02 04:35:12 +00:00
// draw each point
for i, pt := range pts {
var str string
switch {
case i == 0:
str = edgeSegments[flowDir]
case i == len(pts)-1:
str = arrows[flowDir]
default:
prev, next := pts[i-1], pts[i+1]
seg := [2]geo.XY{
prev.Sub(pt),
next.Sub(pt),
}
str = lineSegments[seg]
}
term.MoveCursorTo(pt)
term.Printf(str)
}
2018-06-02 04:35:12 +00:00
// draw the body
if l.body != "" {
bodyPos := mid.Add(geo.Left.Scale(len(l.body) / 2))
term.MoveCursorTo(bodyPos)
term.Printf(l.body)
}
}