Update app.py

app.py

@@ -373,7 +373,7 @@ with gr.Blocks(css=css) as demo:
                   this.onpointerup = function(event) {
                     var pl_a = document.getElementById(\"pl\").getAttribute(\"points\").replace(/\d+,/g, \"\").split(\" \"); 
                     for (var i=0; i<pl_a.length; i++) {
-                      pl_a[i] = pl_a[i] * 2 + 1;
+                      pl_a[i] = parseInt(pl_a[i]) * 2 + 1;
                     }
                     document.getElementsByTagName(\"textarea\")[1].value = pl_a.join(\" \");
                     this.style.borderBottom = \"1px dotted black\";