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// Package simplify implements several reducing/simplifying functions for `orb.Geometry` types.
package simplify
import "github.com/paulmach/orb"
type simplifier interface {
simplify(orb.LineString, bool) (orb.LineString, []int)
}
func simplify(s simplifier, geom orb.Geometry) orb.Geometry {
if geom == nil {
return nil
}
switch g := geom.(type) {
case orb.Point:
return g
case orb.MultiPoint:
if g == nil {
return nil
}
return g
case orb.LineString:
g = lineString(s, g)
if len(g) == 0 {
return nil
}
return g
case orb.MultiLineString:
g = multiLineString(s, g)
if len(g) == 0 {
return nil
}
return g
case orb.Ring:
g = ring(s, g)
if len(g) == 0 {
return nil
}
return g
case orb.Polygon:
g = polygon(s, g)
if len(g) == 0 {
return nil
}
return g
case orb.MultiPolygon:
g = multiPolygon(s, g)
if len(g) == 0 {
return nil
}
return g
case orb.Collection:
g = collection(s, g)
if len(g) == 0 {
return nil
}
return g
case orb.Bound:
return g
}
panic("unsupported type")
}
func lineString(s simplifier, ls orb.LineString) orb.LineString {
return runSimplify(s, ls)
}
func multiLineString(s simplifier, mls orb.MultiLineString) orb.MultiLineString {
for i := range mls {
mls[i] = runSimplify(s, mls[i])
}
return mls
}
func ring(s simplifier, r orb.Ring) orb.Ring {
return orb.Ring(runSimplify(s, orb.LineString(r)))
}
func polygon(s simplifier, p orb.Polygon) orb.Polygon {
count := 0
for i := range p {
r := orb.Ring(runSimplify(s, orb.LineString(p[i])))
if i != 0 && len(r) <= 2 {
continue
}
p[count] = r
count++
}
return p[:count]
}
func multiPolygon(s simplifier, mp orb.MultiPolygon) orb.MultiPolygon {
count := 0
for i := range mp {
p := polygon(s, mp[i])
if len(p[0]) <= 2 {
continue
}
mp[count] = p
count++
}
return mp[:count]
}
func collection(s simplifier, c orb.Collection) orb.Collection {
for i := range c {
c[i] = simplify(s, c[i])
}
return c
}
func runSimplify(s simplifier, ls orb.LineString) orb.LineString {
if len(ls) <= 2 {
return ls
}
ls, _ = s.simplify(ls, false)
return ls
}
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