From cd01d898a8e8148103db4a25f59a2fef0a81fd71 Mon Sep 17 00:00:00 2001
From: Dustin Carlino <dabreegster@gmail.com>
Date: Mon, 5 Dec 2022 14:08:03 +0000
Subject: [PATCH] Move RoadEdge logic out of sidewalk rendering. It'll be
 useful for intersection geometry refactors. #136

---
 osm2streets/src/render.rs | 47 +++++++--------------------------------
 osm2streets/src/road.rs   | 41 ++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 39 deletions(-)

diff --git a/osm2streets/src/render.rs b/osm2streets/src/render.rs
index 3a6b681b..7a77a26b 100644
--- a/osm2streets/src/render.rs
+++ b/osm2streets/src/render.rs
@@ -6,9 +6,8 @@ use std::path::Path;
 use anyhow::Result;
 use geom::{ArrowCap, Distance, Line, PolyLine, Polygon, Ring};
 
-use crate::{
-    DebugStreets, Direction, DrivingSide, Intersection, LaneSpec, LaneType, RoadID, StreetNetwork,
-};
+use crate::road::RoadEdge;
+use crate::{DebugStreets, Direction, DrivingSide, Intersection, LaneType, StreetNetwork};
 
 impl StreetNetwork {
     /// Saves the plain GeoJSON rendering to a file.
@@ -398,43 +397,13 @@ fn make_props(list: &[(&str, serde_json::Value)]) -> serde_json::Map<String, ser
 // TODO Where should this live?
 /// For an intersection, show all corners where sidewalks meet.
 fn make_sidewalk_corners(streets: &StreetNetwork, intersection: &Intersection) -> Vec<Polygon> {
-    #[derive(Clone)]
-    struct Edge {
-        road: RoadID,
-        // Pointed into the intersection
-        pl: PolyLine,
-        lane: LaneSpec,
-    }
-
-    // Get the left and right edge of each road, pointed into the intersection. All sorted
-    // clockwise
-    // TODO Use the road view idea instead. Or just refactor this.
-    let mut edges = Vec::new();
-    for road in streets.roads_per_intersection(intersection.id) {
-        let mut left = Edge {
-            road: road.id,
-            pl: road.center_line.must_shift_left(road.total_width() / 2.0),
-            lane: road.lane_specs_ltr[0].clone(),
-        };
-        let mut right = Edge {
-            road: road.id,
-            pl: road.center_line.must_shift_right(road.total_width() / 2.0),
-            lane: road.lane_specs_ltr.last().unwrap().clone(),
-        };
-        if road.dst_i == intersection.id {
-            edges.push(right);
-            edges.push(left);
-        } else {
-            left.pl = left.pl.reversed();
-            right.pl = right.pl.reversed();
-            edges.push(left);
-            edges.push(right);
-        }
-    }
-
-    // Look at every adjacent pair
-    let mut results = Vec::new();
+    // Look at every adjacent pair of edges
+    let mut edges = RoadEdge::calculate(
+        streets.roads_per_intersection(intersection.id),
+        intersection.id,
+    );
     edges.push(edges[0].clone());
+    let mut results = Vec::new();
     for pair in edges.windows(2) {
         let one = &pair[0];
         let two = &pair[1];
diff --git a/osm2streets/src/road.rs b/osm2streets/src/road.rs
index 28bf05b1..6739eb26 100644
--- a/osm2streets/src/road.rs
+++ b/osm2streets/src/road.rs
@@ -449,3 +449,44 @@ impl StreetNetwork {
         id
     }
 }
+
+/// The edge of a road, pointed into some intersection
+#[derive(Clone)]
+pub(crate) struct RoadEdge {
+    pub road: RoadID,
+    /// Pointed into the intersection
+    pub pl: PolyLine,
+    pub lane: LaneSpec,
+}
+
+impl RoadEdge {
+    /// Get the left and right edge of each road, pointed into the intersection. All sorted
+    /// clockwise. No repetitions -- to iterate over all adjacent pairs, the caller must repeat the
+    /// first edge
+    // TODO Maybe returning an iterator over pairs of these is more useful
+    pub fn calculate(sorted_roads: Vec<&Road>, i: IntersectionID) -> Vec<Self> {
+        let mut edges = Vec::new();
+        for road in sorted_roads {
+            let mut left = RoadEdge {
+                road: road.id,
+                pl: road.center_line.must_shift_left(road.total_width() / 2.0),
+                lane: road.lane_specs_ltr[0].clone(),
+            };
+            let mut right = RoadEdge {
+                road: road.id,
+                pl: road.center_line.must_shift_right(road.total_width() / 2.0),
+                lane: road.lane_specs_ltr.last().unwrap().clone(),
+            };
+            if road.dst_i == i {
+                edges.push(right);
+                edges.push(left);
+            } else {
+                left.pl = left.pl.reversed();
+                right.pl = right.pl.reversed();
+                edges.push(left);
+                edges.push(right);
+            }
+        }
+        edges
+    }
+}