Fixed vertical polylines difficult to select (#7860)

changelog.d/20240507_153530_boris_fixed_vertical_polylines.md

@@ -0,0 +1,4 @@
+### Fixed
+
+- Vertical polyline of two points is difficult to select
+  (<https://github.com/cvat-ai/cvat/pull/7860>)

cvat-core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "cvat-core",
-  "version": "15.0.4",
+  "version": "15.0.5",
   "type": "module",
   "description": "Part of Computer Vision Tool which presents an interface for client-side integration",
   "main": "src/api.ts",

cvat-core/src/annotations-objects.ts

@@ -1671,7 +1671,16 @@ export class PolylineShape extends PolyShape {
             const y2 = points[i + 3];
 
             // Find the shortest distance from point to an edge
-            if ((x - x1) * (x2 - x) >= 0 && (y - y1) * (y2 - y) >= 0) {
+            // using perpendicular or by the distance to the nearest point
+
+            // Get coordinate vectors
+            const AB = [x2 - x1, y2 - y1];
+            const BM = [x - x2, y - y2];
+            const AM = [x - x1, y - y1];
+
+            // scalar products have different signs for two pairs of vectors
+            // it means that perpendicular projection lies on the edge
+            if (Math.sign(AB[0] * BM[0] + AB[1] * BM[1]) !== Math.sign(AB[0] * AM[0] + AB[1] * AM[1])) {
                 // Find the length of a perpendicular
                 // https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line
                 distances.push(