Adds CurvedLineSymbolizer

src/labeler.ts

@@ -18,6 +18,8 @@ export interface Label {
   draw: (ctx: any, drawExtra?: DrawExtra) => void;
   deduplicationKey?: string;
   deduplicationDistance?: number;
+  allowCollisions?: boolean;
+  collisionKey?: string;
 }
 
 export interface IndexedLabel {
@@ -135,7 +137,14 @@ export class Index {
   public labelCollides(label: Label, order: number): boolean {
     for (let bbox of label.bboxes) {
       for (let match of this.tree.search(bbox)) {
-        if (match.indexed_label.order <= order) return true;
+        if (match.indexed_label.order <= order) {
+          if (
+            !!label.allowCollisions &&
+            match.collisionKey === label.collisionKey
+          )
+            return false;
+          return true;
+        }
       }
     }
     return false;
@@ -187,6 +196,7 @@ export class Index {
     for (let bbox of label.bboxes) {
       var b: any = bbox;
       b.indexed_label = indexed_label;
+      if (label.collisionKey) b.collisionKey = label.collisionKey;
       this.tree.insert(b);
 
       if (bbox.minX < 0) wrapsLeft = true;

src/line.ts

@@ -98,7 +98,8 @@ export function simpleLabel(
   mls: any,
   minimum: number,
   repeatDistance: number,
-  cellSize: number
+  cellSize: number,
+  overflowAllowed = false
 ): LabelCandidate[] {
   let longestStart;
   let longestEnd;
@@ -111,7 +112,7 @@ export function simpleLabel(
   for (let ls of mls) {
     let segments = linelabel(ls, Math.PI / 90); // 2 degrees, close to a straight line
     for (let segment of segments) {
-      if (segment.length >= minimum + cellSize) {
+      if (segment.length >= minimum + cellSize || overflowAllowed) {
         let start = new Point(
           ls[segment.beginIndex].x,
           ls[segment.beginIndex].y
@@ -125,8 +126,8 @@ export function simpleLabel(
         // offset from the start by cellSize to allow streets that meet at right angles
         // to both be labeled.
         for (
-          var i = cellSize;
-          i < segment.length - minimum;
+          var i = overflowAllowed ? 0 : cellSize;
+          i < segment.length - (overflowAllowed ? 0 : minimum);
           i += repeatDistance
         ) {
           candidates.push({

src/maths.ts

@@ -0,0 +1,8 @@
+// @ts-ignore
+import Point from "@mapbox/point-geometry";
+export type Vector = Point;
+
+export const normalize = (v: Vector): Vector => {
+  const vectorMagnitude = Math.hypot(v.x, v.y);
+  return { x: v.x / vectorMagnitude, y: v.y / vectorMagnitude };
+};