新增刪除測量功能

index.php

@@ -457,6 +457,13 @@ if (!isset($_SESSION['loggedin'])) {
 					}
 				});
 
+			document
+				.getElementById("clear")
+				.addEventListener("click", (event) => {
+					setActiveWidget(null);
+					setActiveButton(null);
+				});
+
 			function setActiveWidget(type) {
 				switch (type) {
 					case "distance":
@@ -491,6 +498,7 @@ if (!isset($_SESSION['loggedin'])) {
 						view.ui.add(activeWidget, "bottom-left");
 						setActiveButton(document.getElementById("areaButton"));
 						break;
+
 					case null:
 						if (activeWidget) {
 							view.ui.remove(activeWidget);
@@ -504,7 +512,7 @@ if (!isset($_SESSION['loggedin'])) {
 			function setActiveButton(selectedButton) {
 				// focus the view to activate keyboard shortcuts for sketching
 				view.focus();
-				const elements = document.getElementsByClassName("active");
+				const elements = document.getElementById("topbar").getElementsByClassName("active");
 				for (let i = 0; i < elements.length; i++) {
 					elements[i].classList.remove("active");
 				}