Generate arrows manually. #68

a-b-street · Jan 4, 2025 · 19b6e2c · 19b6e2c
1 parent 3cee358
commit 19b6e2c
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Showing 4 changed files with 115 additions and 31 deletions.
diff --git a/backend/src/geo_helpers.rs b/backend/src/geo_helpers.rs
@@ -1,6 +1,6 @@
 use geo::{
-    BoundingRect, Contains, Coord, Distance, Euclidean, Intersects, Line, LineInterpolatePoint,
-    LineIntersection, LineLocatePoint, LineString, Point, Polygon, Rect,
+    BoundingRect, Contains, Coord, Distance, Euclidean, Intersects, Length, Line,
+    LineInterpolatePoint, LineIntersection, LineLocatePoint, LineString, Point, Polygon, Rect,
 };
 use rstar::AABB;
 use utils::LineSplit;
@@ -125,8 +125,91 @@ pub fn limit_angle(a1: f64) -> f64 {
 
 pub fn euclidean_destination(pt: Point, angle_degs: f64, dist_away_m: f64) -> Point {
     let (sin, cos) = angle_degs.to_radians().sin_cos();
-    Point::new(
-        pt.x() + dist_away_m * cos,
-        pt.y() + dist_away_m * sin,
-    )
+    Point::new(pt.x() + dist_away_m * cos, pt.y() + dist_away_m * sin)
+}
+
+fn euclidean_destination_coord(pt: Coord, angle_degs: f64, dist_away_m: f64) -> Coord {
+    euclidean_destination(pt.into(), angle_degs, dist_away_m).into()
+}
+
+// If the line is too short for the thickness, give up
+pub fn make_arrow(line: Line, thickness: f64, double_ended: bool) -> Option<Polygon> {
+    let head_size = thickness * 2.0;
+    let triangle_height = head_size / 2.0_f64.sqrt();
+    let angle = angle_of_line(line);
+    let length = line.length::<Euclidean>();
+
+    if length < triangle_height * 3.0 {
+        return None;
+    }
+
+    let mut pts = Vec::new();
+
+    let start_trimmed = euclidean_destination_coord(line.start, angle, triangle_height);
+    let end_trimmed = euclidean_destination_coord(line.start, angle, length - triangle_height);
+
+    if double_ended {
+        pts.push(line.start);
+        pts.push(euclidean_destination_coord(
+            start_trimmed,
+            angle + 90.0,
+            thickness * 1.5,
+        ));
+        pts.push(euclidean_destination_coord(
+            start_trimmed,
+            angle + 90.0,
+            thickness * 0.5,
+        ));
+    } else {
+        pts.push(euclidean_destination_coord(
+            line.start,
+            angle + 90.0,
+            thickness * 0.5,
+        ));
+    }
+    pts.push(euclidean_destination_coord(
+        end_trimmed,
+        angle + 90.0,
+        thickness * 0.5,
+    ));
+    pts.push(euclidean_destination_coord(
+        end_trimmed,
+        angle + 90.0,
+        thickness * 1.5,
+    ));
+
+    pts.push(line.end);
+
+    pts.push(euclidean_destination_coord(
+        end_trimmed,
+        angle - 90.0,
+        thickness * 1.5,
+    ));
+    pts.push(euclidean_destination_coord(
+        end_trimmed,
+        angle - 90.0,
+        thickness * 0.5,
+    ));
+    if double_ended {
+        pts.push(euclidean_destination_coord(
+            start_trimmed,
+            angle - 90.0,
+            thickness * 0.5,
+        ));
+        pts.push(euclidean_destination_coord(
+            start_trimmed,
+            angle - 90.0,
+            thickness * 1.5,
+        ));
+    } else {
+        pts.push(euclidean_destination_coord(
+            line.start,
+            angle - 90.0,
+            thickness * 0.5,
+        ));
+    }
+
+    pts.push(pts[0]);
+
+    Some(Polygon::new(LineString::new(pts), Vec::new()))
 }
diff --git a/backend/src/neighbourhood.rs b/backend/src/neighbourhood.rs
@@ -2,13 +2,15 @@ use std::collections::{BTreeMap, BTreeSet};
 
 use anyhow::Result;
 use geo::{
-    Line, Area, Distance, Euclidean, Length, LineInterpolatePoint, LineLocatePoint, LineString, Point,
-    Polygon, PreparedGeometry, Relate,
+    Area, Distance, Euclidean, Length, Line, LineInterpolatePoint, LineLocatePoint, LineString,
+    Point, Polygon, PreparedGeometry, Relate,
 };
 use geojson::{Feature, FeatureCollection};
 use web_time::Instant;
 
-use crate::geo_helpers::{aabb, angle_of_line, buffer_aabb, clip_linestring_to_polygon, euclidean_destination};
+use crate::geo_helpers::{
+    aabb, angle_of_line, buffer_aabb, clip_linestring_to_polygon, euclidean_destination, make_arrow,
+};
 use crate::render_cells::Color;
 use crate::{Cell, Direction, IntersectionID, MapModel, RenderCells, RoadID, Shortcuts};
 
@@ -254,11 +256,14 @@ impl Neighbourhood {
                 std::mem::swap(&mut line.start, &mut line.end);
             }
 
-            let mut f = map.mercator.to_wgs84_gj(&line);
-            // TODO Which cell?
-            f.set_property("kind", "border_arrow");
-            f.set_property("oneway", map.directions[r] != Direction::BothWays);
-            features.push(f);
+            let thickness = 6.0;
+            let double_ended = map.directions[r] == Direction::BothWays;
+            if let Some(polygon) = make_arrow(line, thickness, double_ended) {
+                let mut f = map.mercator.to_wgs84_gj(&polygon);
+                // TODO Which cell?
+                f.set_property("kind", "border_arrow");
+                features.push(f);
+            }
         }
         features
     }

diff --git a/web/src/RenderNeighbourhood.svelte b/web/src/RenderNeighbourhood.svelte
@@ -6,7 +6,6 @@
     GeoJSON,
     hoverStateFilter,
     LineLayer,
-    SymbolLayer,
   } from "svelte-maplibre";
   import { layerId } from "./common";
   import OneWayLayer from "./OneWayLayer.svelte";
@@ -95,27 +94,22 @@
     }}
   />
 
-  <!--
-  <LineLayer
-    {...layerId("border-arrow-bases")}
+  <FillLayer
+    {...layerId("border-arrows")}
     filter={["==", ["get", "kind"], "border_arrow"]}
     paint={{
-      "line-width": 10,
-      "line-color": "cyan",
+      "fill-color": "cyan",
+      "fill-opacity": 0.5,
     }}
   />
-
-  <SymbolLayer
-    {...layerId("border-arrows")}
+  <LineLayer
+    {...layerId("border-arrow-outlines")}
     filter={["==", ["get", "kind"], "border_arrow"]}
-    layout={{
-      "icon-image": "oneway-arrow",
-      "icon-size": 1.0,
-      "symbol-placement": "line",
-      "icon-allow-overlap": true,
+    paint={{
+      "line-color": "black",
+      "line-width": 2,
     }}
   />
-  -->
 
   <LineLayer
     {...layerId("interior-roads-outlines")}

diff --git a/web/src/common/zorder.ts b/web/src/common/zorder.ts
@@ -89,8 +89,6 @@ const layerZorder = [
   "cells",
   "interior-roads-outlines",
   "interior-roads",
-  "border-arrow-bases",
-  "border-arrows",
 
   "compare-route",
 
@@ -114,6 +112,10 @@ const layerZorder = [
   "boundary",
   "neighbourhood-boundary",
 
+  // These're outside the neighbourhood-boundary, but don't fade them
+  "border-arrows",
+  "border-arrow-outlines",
+
   "auto-boundaries-areas",
   "auto-boundaries-severances",