1 files changed, 4 insertions, 0 deletions
diff --git a/src/Utils.ts b/src/Utils.ts
index 6fc00040f..bf1f72774 100644
--- a/src/Utils.ts
+++ b/src/Utils.ts
@@ -243,6 +243,10 @@ export namespace Utils {
         return [Math.sqrt((ys2 - ye) * (ys2 - ye) + (x2 - x) * (x2 - x)), [x, ye, x, ye]];
     }
 
+    export function rotPt(x: number, y: number, radAng: number) {
+        return { x: x * Math.cos(radAng) - y * Math.sin(radAng), y: x * Math.sin(radAng) + y * Math.cos(radAng) };
+    }
+
     function project(px: number, py: number, ax: number, ay: number, bx: number, by: number) {
         if (ax === bx && ay === by) return { point: { x: ax, y: ay }, left: false, dot: 0, t: 0 };
         const atob = { x: bx - ax, y: by - ay };