razzius/synchronized_polygons.html

## synchronized_polygons.html
<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Draggable Polygons</title>
    <style>
      /* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
      #map {
        height: 100%;
      }
      /* Optional: Makes the sample page fill the window. */
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <script>
      // This example creates draggable triangles on the map.
      // Note also that the red triangle is geodesic, so its shape changes
      // as you drag it north or south.

      function initMap() {

        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 5,
          center: {lat: 24.886, lng: -70.268},
          mapTypeId: 'terrain'
        });

        var blueCoords = [
          {lat: 25.774, lng: -60.190},
          {lat: 18.466, lng: -46.118},
          {lat: 32.321, lng: -44.757}
        ];

        var redCoords = [
          {lat: 25.774, lng: -80.190},
          {lat: 18.466, lng: -66.118},
          {lat: 32.321, lng: -64.757}
        ];

        // Construct a draggable red triangle with geodesic set to true.
        window.red = new google.maps.Polygon({
          map: map,
          paths: redCoords,
          strokeColor: '#FF0000',
          strokeOpacity: 0.8,
          strokeWeight: 2,
          fillColor: '#FF0000',
          fillOpacity: 0.35,
          draggable: true,
          geodesic: true
        });

        // Construct a draggable blue triangle with geodesic set to false.
        blue = new google.maps.Polygon({
          map: map,
          paths: blueCoords,
          strokeColor: '#0000FF',
          strokeOpacity: 0.8,
          strokeWeight: 2,
          fillColor: '#0000FF',
          fillOpacity: 0.35,
          draggable: true,
          geodesic: false
        });

        function getPolygonCenter(polygon) {
          var bounds = new google.maps.LatLngBounds();
          polygon.getPath().getArray().forEach(p => bounds.extend(p))
          return bounds.getCenter()
        }

        function movePolygon(polygon, newCenter) {
          const center = getPolygonCenter(polygon)
          const dlat = newCenter.lat() - center.lat()
          const dlng = newCenter.lng() - center.lng()

          const points = polygon.getPath().getArray()
          const updated = points.map(point => new google.maps.LatLng(point.lat() + dlat, point.lng() + dlng))
          polygon.setPath(updated)
        }

        red.addListener('dragstart', () => {
          start = getPolygonCenter(red)
          blueCenter = getPolygonCenter(blue)
        })

        red.addListener('drag', () => {
          const center = getPolygonCenter(red)
          console.log(start.lng(), start.lat(), center.lng(), center.lat())
          const dlat = center.lat() - start.lat()
          const dlng = center.lng() - start.lng()

          const newlat = blueCenter.lat() + dlat
          const newlng = blueCenter.lng() + dlng
          const newCenter = new google.maps.LatLng(newlat, newlng)
          movePolygon(blue, newCenter)
        })
      }
    </script>
    <script async defer
    src="https://maps.googleapis.com/maps/api/js?key=AIzaSyAy-jGmWYsIo0ufT8BsC5z1KBPKd8sXGHA&callback=initMap">
    </script>
  </body>
</html>
	<!DOCTYPE html>
	<html>
	<head>
	<meta name="viewport" content="initial-scale=1.0, user-scalable=no">
	<meta charset="utf-8">
	<title>Draggable Polygons</title>
	<style>
	/* Always set the map height explicitly to define the size of the div
	* element that contains the map. */
	#map {
	height: 100%;
	}
	/* Optional: Makes the sample page fill the window. */
	html, body {
	height: 100%;
	margin: 0;
	padding: 0;
	}
	</style>
	</head>
	<body>
	<div id="map"></div>
	<script>
	// This example creates draggable triangles on the map.
	// Note also that the red triangle is geodesic, so its shape changes
	// as you drag it north or south.

	function initMap() {

	var map = new google.maps.Map(document.getElementById('map'), {
	zoom: 5,
	center: {lat: 24.886, lng: -70.268},
	mapTypeId: 'terrain'
	});

	var blueCoords = [
	{lat: 25.774, lng: -60.190},
	{lat: 18.466, lng: -46.118},
	{lat: 32.321, lng: -44.757}
	];

	var redCoords = [
	{lat: 25.774, lng: -80.190},
	{lat: 18.466, lng: -66.118},
	{lat: 32.321, lng: -64.757}
	];

	// Construct a draggable red triangle with geodesic set to true.
	window.red = new google.maps.Polygon({
	map: map,
	paths: redCoords,
	strokeColor: '#FF0000',
	strokeOpacity: 0.8,
	strokeWeight: 2,
	fillColor: '#FF0000',
	fillOpacity: 0.35,
	draggable: true,
	geodesic: true
	});

	// Construct a draggable blue triangle with geodesic set to false.
	blue = new google.maps.Polygon({
	map: map,
	paths: blueCoords,
	strokeColor: '#0000FF',
	strokeOpacity: 0.8,
	strokeWeight: 2,
	fillColor: '#0000FF',
	fillOpacity: 0.35,
	draggable: true,
	geodesic: false
	});

	function getPolygonCenter(polygon) {
	var bounds = new google.maps.LatLngBounds();
	polygon.getPath().getArray().forEach(p => bounds.extend(p))
	return bounds.getCenter()
	}

	function movePolygon(polygon, newCenter) {
	const center = getPolygonCenter(polygon)
	const dlat = newCenter.lat() - center.lat()
	const dlng = newCenter.lng() - center.lng()

	const points = polygon.getPath().getArray()
	const updated = points.map(point => new google.maps.LatLng(point.lat() + dlat, point.lng() + dlng))
	polygon.setPath(updated)
	}

	red.addListener('dragstart', () => {
	start = getPolygonCenter(red)
	blueCenter = getPolygonCenter(blue)
	})

	red.addListener('drag', () => {
	const center = getPolygonCenter(red)
	console.log(start.lng(), start.lat(), center.lng(), center.lat())
	const dlat = center.lat() - start.lat()
	const dlng = center.lng() - start.lng()

	const newlat = blueCenter.lat() + dlat
	const newlng = blueCenter.lng() + dlng
	const newCenter = new google.maps.LatLng(newlat, newlng)
	movePolygon(blue, newCenter)
	})
	}
	</script>
	<script async defer
	src="https://maps.googleapis.com/maps/api/js?key=AIzaSyAy-jGmWYsIo0ufT8BsC5z1KBPKd8sXGHA&callback=initMap">
	</script>
	</body>
	</html>