add clicked point example notebook

examples/clicked-point.ipynb

@@ -0,0 +1,68 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "e328a21f-5254-42ee-9683-136561d96886",
+   "metadata": {},
+   "source": [
+    "# Clicked point\n",
+    "\n",
+    "This notebook demonstrates how you can access the coordinate of the most recent click on a Lonboard map and update a set of widgets to display the x and y coordinates using the [`ipywidgets.observe`](https://ipywidgets.readthedocs.io/en/8.1.5/examples/Widget%20Events.html#traitlet-events) method."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "f986a64e-269f-4966-93b0-cfa5bf1ba882",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import ipywidgets as widgets\n",
+    "import traitlets\n",
+    "\n",
+    "from lonboard import Map\n",
+    "\n",
+    "## Create a Lonboard map and two widgets to display the coordinate\n",
+    "m = Map(layers=[])\n",
+    "clicked_x_display = widgets.FloatText(description=\"last clicked x:\")\n",
+    "clicked_y_display = widgets.FloatText(description=\"last clicked y:\")\n",
+    "\n",
+    "## create a function that accepts the event which fires when we single click in\n",
+    "##  the map while we are not in bounding box selection mode\n",
+    "def on_map_click(event: traitlets.utils.bunch.Bunch) -> None:\n",
+    "    x,y = event.get(\"new\")\n",
+    "    clicked_x_display.value = x\n",
+    "    clicked_y_display.value = y\n",
+    "m.observe(on_map_click, \"clicked_point\")\n",
+    "\n",
+    "## show the widgets\n",
+    "widgets.VBox([\n",
+    "    m,\n",
+    "    clicked_x_display,\n",
+    "    clicked_y_display\n",
+    "])"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "lonboard",
+   "language": "python",
+   "name": "lonboard"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.11.4"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}