/
path.go
210 lines (187 loc) · 4.1 KB
/
path.go
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package ln
import (
"fmt"
"io/ioutil"
"strings"
"github.com/fogleman/gg"
)
type Path []Vector
func (p Path) BoundingBox() Box {
box := Box{p[0], p[0]}
for _, v := range p {
box = box.Extend(Box{v, v})
}
return box
}
func (p Path) Transform(matrix Matrix) Path {
var result Path
for _, v := range p {
result = append(result, matrix.MulPosition(v))
}
return result
}
func (p Path) Chop(step float64) Path {
var result Path
for i := 0; i < len(p)-1; i++ {
a := p[i]
b := p[i+1]
v := b.Sub(a)
l := v.Length()
if i == 0 {
result = append(result, a)
}
d := step
for d < l {
result = append(result, a.Add(v.MulScalar(d/l)))
d += step
}
result = append(result, b)
}
return result
}
func (p Path) Filter(f Filter) Paths {
var result Paths
var path Path
for _, v := range p {
v, ok := f.Filter(v)
// ok = ok || i%8 < 4 // show hidden lines
if ok {
path = append(path, v)
} else {
if len(path) > 1 {
result = append(result, path)
}
path = nil
}
}
if len(path) > 1 {
result = append(result, path)
}
return result
}
func (p Path) Simplify(threshold float64) Path {
if len(p) < 3 {
return p
}
a := p[0]
b := p[len(p)-1]
index := -1
distance := 0.0
for i := 1; i < len(p)-1; i++ {
d := p[i].SegmentDistance(a, b)
if d > distance {
index = i
distance = d
}
}
if distance > threshold {
r1 := p[:index+1].Simplify(threshold)
r2 := p[index:].Simplify(threshold)
return append(r1[:len(r1)-1], r2...)
} else {
return Path{a, b}
}
}
func (p Path) Print() {
for _, v := range p {
fmt.Printf("%g,%g;", v.X, v.Y)
}
fmt.Println()
}
func (p Path) String() string {
var parts []string
for _, v := range p {
parts = append(parts, fmt.Sprintf("%g,%g", v.X, v.Y))
}
return strings.Join(parts, ";")
}
func (p Path) ToSVG() string {
var coords []string
for _, v := range p {
coords = append(coords, fmt.Sprintf("%f,%f", v.X, v.Y))
}
points := strings.Join(coords, " ")
return fmt.Sprintf("<polyline stroke=\"black\" fill=\"none\" points=\"%s\" />", points)
}
type Paths []Path
func (p Paths) BoundingBox() Box {
box := p[0].BoundingBox()
for _, path := range p {
box = box.Extend(path.BoundingBox())
}
return box
}
func (p Paths) Transform(matrix Matrix) Paths {
var result Paths
for _, path := range p {
result = append(result, path.Transform(matrix))
}
return result
}
func (p Paths) Chop(step float64) Paths {
var result Paths
for _, path := range p {
result = append(result, path.Chop(step))
}
return result
}
func (p Paths) Filter(f Filter) Paths {
var result Paths
for _, path := range p {
result = append(result, path.Filter(f)...)
}
return result
}
func (p Paths) Simplify(threshold float64) Paths {
var result Paths
for _, path := range p {
result = append(result, path.Simplify(threshold))
}
return result
}
func (p Paths) Print() {
for _, path := range p {
path.Print()
}
}
func (p Paths) String() string {
var parts []string
for _, path := range p {
parts = append(parts, path.String())
}
return strings.Join(parts, "\n")
}
func (p Paths) WriteToPNG(path string, width, height float64) {
scale := 1.0
w, h := int(width*scale), int(height*scale)
dc := gg.NewContext(w, h)
dc.InvertY()
dc.SetRGB(1, 1, 1)
dc.Clear()
dc.SetRGB(0, 0, 0)
dc.SetLineWidth(3)
for _, path := range p {
for _, v := range path {
dc.LineTo(v.X*scale, v.Y*scale)
}
dc.NewSubPath()
}
dc.Stroke()
dc.SavePNG(path)
}
func (p Paths) ToSVG(width, height float64) string {
var lines []string
lines = append(lines, fmt.Sprintf("<svg width=\"%f\" height=\"%f\" version=\"1.1\" baseProfile=\"full\" xmlns=\"http://www.w3.org/2000/svg\">", width, height))
lines = append(lines, fmt.Sprintf("<g transform=\"translate(0,%f) scale(1,-1)\">", height))
for _, path := range p {
lines = append(lines, path.ToSVG())
}
lines = append(lines, "</g></svg>")
return strings.Join(lines, "\n")
}
func (p Paths) WriteToSVG(path string, width, height float64) error {
return ioutil.WriteFile(path, []byte(p.ToSVG(width, height)), 0644)
}
func (p Paths) WriteToTXT(path string) error {
return ioutil.WriteFile(path, []byte(p.String()), 0644)
}