update point B position on click before freezing tracking

line-segment-intersection/src/App.svelte

@@ -76,7 +76,20 @@
     };
   }
 
-  function handleCanvasClick() {
+  function handleCanvasClick(event) {
+    // If we're about to turn off tracking, update position one last time
+    if (trackHover) {
+      const rect = canvas.getBoundingClientRect();
+      const mouseX = event.clientX - rect.left;
+      const mouseY = event.clientY - rect.top;
+
+      // Add half grid unit offset for snapping to closest grid intersection
+      userPoint = {
+        x: Math.floor((mouseX + GRID_SIZE / 2) / GRID_SIZE),
+        y: Math.floor((HEIGHT - mouseY + GRID_SIZE / 2) / GRID_SIZE)
+      };
+    }
+
     trackHover = !trackHover;
   }