From 2082ef149c56e0cb96c316bde8cf589b03bc28fd Mon Sep 17 00:00:00 2001
From: Mark Tolmacs <mark@lazycat.hu>
Date: Wed, 7 May 2025 22:27:49 +0200
Subject: [PATCH] Linear distance calc

Signed-off-by: Mark Tolmacs <mark@lazycat.hu>
---
 packages/element/src/distance.ts | 62 +++++++++++++++++++++++---------
 1 file changed, 45 insertions(+), 17 deletions(-)

diff --git a/packages/element/src/distance.ts b/packages/element/src/distance.ts
index 88ce640e1..43482c87e 100644
--- a/packages/element/src/distance.ts
+++ b/packages/element/src/distance.ts
@@ -1,8 +1,8 @@
 import {
   curvePointDistance,
   distanceToLineSegment,
-  lineSegment,
-  pointFrom,
+  isCurve,
+  isLineSegment,
   pointRotateRads,
 } from "@excalidraw/math";
 
@@ -10,10 +10,16 @@ import { ellipse, ellipseDistanceFromPoint } from "@excalidraw/math/ellipse";
 
 import { elementCenterPoint } from "@excalidraw/common";
 
-import type { GlobalPoint, Radians } from "@excalidraw/math";
+import type {
+  Curve,
+  GlobalPoint,
+  LineSegment,
+  Radians,
+} from "@excalidraw/math";
 
 import {
   deconstructDiamondElement,
+  deconstructLinearOrFreeDrawElement,
   deconstructRectanguloidElement,
 } from "./utils";
 
@@ -21,6 +27,8 @@ import type {
   ExcalidrawDiamondElement,
   ExcalidrawElement,
   ExcalidrawEllipseElement,
+  ExcalidrawFreeDrawElement,
+  ExcalidrawLinearElement,
   ExcalidrawRectanguloidElement,
 } from "./types";
 
@@ -45,20 +53,7 @@ export const distanceToElement = (
     case "line":
     case "arrow":
     case "freedraw":
-      return element.points.reduce((acc, point, idx) => {
-        if (idx === 0) {
-          return acc;
-        }
-        const prevPoint = element.points[idx - 1];
-        const segment = lineSegment(
-          pointFrom<GlobalPoint>(
-            element.x + prevPoint[0],
-            element.y + prevPoint[1],
-          ),
-          pointFrom<GlobalPoint>(element.x + point[0], element.y + point[1]),
-        );
-        return Math.min(acc, distanceToLineSegment(p, segment));
-      }, Infinity);
+      return distanceToLinearOrFreeDraElement(element, p);
   }
 };
 
@@ -137,3 +132,36 @@ const distanceToEllipseElement = (
     ellipse(center, element.width / 2, element.height / 2),
   );
 };
+
+const distanceToLinearOrFreeDraElement = (
+  element: ExcalidrawLinearElement | ExcalidrawFreeDrawElement,
+  p: GlobalPoint,
+) => {
+  const shapes = deconstructLinearOrFreeDrawElement(element);
+  let distance = Infinity;
+
+  for (const shape of shapes) {
+    switch (true) {
+      case isCurve(shape): {
+        const d = curvePointDistance(shape as Curve<GlobalPoint>, p);
+
+        if (d < distance) {
+          distance = d;
+        }
+
+        continue;
+      }
+      case isLineSegment(shape): {
+        const d = distanceToLineSegment(p, shape as LineSegment<GlobalPoint>);
+
+        if (d < distance) {
+          distance = d;
+        }
+
+        continue;
+      }
+    }
+  }
+
+  return distance;
+};