1 files changed, 25 insertions, 5 deletions

diff --git a/lib/src/graph.cpp b/lib/src/graph.cpp
index c75d466..1c770e9 100644
--- a/lib/src/graph.cpp
+++ b/lib/src/graph.cpp
@@ -445,14 +445,14 @@ void graph::helper(unsigned nv, std::mt19937& rng) {
   jcv_diagram_free(&diagram);
 }
 
-graph::coordinate reverse(const graph::coordinate& x) { return {x.y, x.x}; }
+coordinate reverse(const coordinate& x) { return {x.y, x.x}; }
 
 graph const graph::rotate() {
   graph g2(*this);
 
   for (graph::vertex& v : g2.vertices) {
     v.r = reverse(v.r);
-    for (graph::coordinate& r : v.polygon) {
+    for (coordinate& r : v.polygon) {
       r = reverse(r);
     }
   }
@@ -464,7 +464,7 @@ graph const graph::rotate() {
 
   for (graph::vertex& v : g2.dual_vertices) {
     v.r = reverse(v.r);
-    for (graph::coordinate& r : v.polygon) {
+    for (coordinate& r : v.polygon) {
       r = reverse(r);
     }
   }
@@ -490,7 +490,7 @@ std::string graph::write() const {
   output += "},\"vp\"->{";
   for (const graph::vertex &v : vertices) {
     output += "{";
-    for (const graph::coordinate &r : v.polygon) {
+    for (const coordinate &r : v.polygon) {
       output += "{" + std::to_string(r.x) + "," + std::to_string(r.y) + "},";
     }
     output.pop_back();
@@ -505,7 +505,7 @@ std::string graph::write() const {
   output += "},\"up\"->{";
   for (const graph::vertex &v : dual_vertices) {
     output += "{";
-    for (const graph::coordinate &r : v.polygon) {
+    for (const coordinate &r : v.polygon) {
       output += "{" + std::to_string(r.x) + "," + std::to_string(r.y) + "},";
     }
     output.pop_back();
@@ -536,3 +536,23 @@ std::string graph::write() const {
 
   return output;
 }
+
+coordinate graph::Δr(unsigned e) const {
+  coordinate tmp = dual_vertices[dual_edges[e].v[1]].r - dual_vertices[dual_edges[e].v[0]].r;
+  if (dual_edges[e].crossings[0]) {
+    if (tmp.x > 0) {
+      tmp.x -= L.x;
+    } else {
+      tmp.x += L.x;
+    }
+  }
+  if (dual_edges[e].crossings[1]) {
+    if (tmp.y > 0) {
+      tmp.y -= L.y;
+    } else {
+      tmp.y += L.y;
+    }
+  }
+
+  return tmp;
+}