add getLength function for polyline

looksgood · May 9, 2020 · 6beb5bb · 6beb5bb
1 parent dd5424c
commit 6beb5bb
Show file tree

Hide file tree

Showing 3 changed files with 23 additions and 2 deletions.
diff --git a/src/polyline.cc b/src/polyline.cc
@@ -8,6 +8,7 @@ Napi::Object Polyline::Init(Napi::Env env, Napi::Object exports) {
   Napi::Function func = DefineClass(env, "Polyline", {
     InstanceMethod("contains", &Polyline::Contains),
     InstanceMethod("nearlyCovers", &Polyline::NearlyCovers),
+    InstanceMethod("getLength", &Polyline::GetLength),
   });
 
   constructor = Napi::Persistent(func);
@@ -111,4 +112,11 @@ S2Polyline* Polyline::Get() {
   return this->s2polyline.Clone();
 }
 
+Napi::Value Polyline::GetLength(const Napi::CallbackInfo& info){
+  double length = 1;
+  Napi::Env env = info.Env();
+  S1Angle s1Angle = this->s2polyline.GetLength();
+  length = S2Earth::ToMeters(s1Angle);
 
+  return Napi::Number::New(env, length);
+}
diff --git a/src/polyline.h b/src/polyline.h
@@ -6,6 +6,7 @@
 #include "latlng.h"
 #include "cell.h"
 #include "s2/s1angle.h"
+#include "s2/s2earth.h"
 #include "s2/s2pointutil.h"
 #include "s2/s2polyline.h"
 #include "s2/base/stringprintf.h"
@@ -21,6 +22,7 @@ class Polyline : public Napi::ObjectWrap<Polyline> {
   private:
     Napi::Value Contains(const Napi::CallbackInfo &info);
     Napi::Value NearlyCovers(const Napi::CallbackInfo &info);
+    Napi::Value GetLength(const Napi::CallbackInfo &info);
 
     S2Polyline s2polyline;
 };

diff --git a/test/Polyline.test.js b/test/Polyline.test.js
@@ -44,6 +44,7 @@ test("Polyline#NearlyCovers true", () => {
   });
   const polyline = new s2.Polyline(lls);
 
+
   const newBaiCauseway = [[30.261254, 120.147342],[30.260202, 120.146395],[30.258967, 120.145267],[30.257545, 120.144089], [30.256662, 120.143349],[30.256027, 120.142843],[30.255445, 120.142336],[30.254703, 120.141366]];
   const newLls = newBaiCauseway.map((latlng) => {
     const [lat, lng] = latlng;
@@ -69,7 +70,17 @@ test("Polyline#NearlyCovers false", () => {
     const [lat, lng] = latlng;
     return new s2.LatLng(lat, lng);
   });
-  const newPolyline = new s2.Polyline(newLls);
+  const newPolyline = new s2.Polyline(newLls); 
 
   expect(polyline.nearlyCovers(newPolyline, 1e-3)).toBe(false);
-});
+});
+
+test("Polyline#getLength", () => {
+  const lls = baiCauseway.map((latlng) => {
+    const [lat, lng] = latlng;
+    return new s2.LatLng(lat, lng);
+  });
+  const polyline = new s2.Polyline(lls);
+
+  expect(polyline.getLength()).toBe(805.4416481053961);
+});