maptalks - 屏幕坐标转换

屏幕坐标转换

index.html

<!DOCTYPE html>
<html>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>地图 - 屏幕坐标转换</title>
  <style type="text/css">
    html,body{margin:0px;height:100%;width:100%}
    .container{width:100%;height:100%}
    #coordinate{position:fixed;left:0px;top:0px;width:100%;height:95px;overflow:hidden}
    #coordinate div{background-color:rgba(13, 13, 13, 0.5);width:100%;height:100%;padding:10px 10px 10px 10px;font:13px bold sans-serif;color:#fff}
  </style>
  <link rel="stylesheet" href="https://unpkg.com/maptalks/dist/maptalks.css">
  <script type="text/javascript" src="https://unpkg.com/maptalks/dist/maptalks.min.js"></script>
  <body>

    <div id="map" class="container"></div>
    <div id="coordinate"></div>

    <script>

      var map = new maptalks.Map('map', {
        center: [-0.113049,51.498568],
        zoom: 14,
        centerCross : true,
        baseLayer: new maptalks.TileLayer('base', {
          urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
          subdomains: ['a','b','c','d'],
          attribution: '&copy; <a href="http://osm.org">OpenStreetMap</a> contributors, &copy; <a href="https://carto.com/">CARTO</a>'
        })
      });

      map.on('moving moveend zoomend', update);

      update();

      function update() {
        var projection = map.getProjection();
        var center = map.getCenter(),
          prj = projection.project(center),
          containerPoint = map.coordinateToContainerPoint(center).round();

        document.getElementById('coordinate').innerHTML = '<div>' + [
          'Center : [' + center.x.toFixed(5) + ', ' + center.y.toFixed(5) + ']',
          'Projected Coordinate : [' + prj.x.toFixed(5) + ', ' + prj.y.toFixed(5) + ']',
          'ContainerPoint is the screen position in px from northwest of the map container.',
          'ContainerPoint : [' + containerPoint.x + ', ' + containerPoint.y + ']'
        ].join('<br>') + '</div>';
      }

    </script>
  </body>
</html>

var map = new maptalks.Map('map', {
  center: [-0.113049, 51.498568],
  zoom: 14,
  centerCross: true,
  baseLayer: new maptalks.TileLayer('base', {
    urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
    subdomains: ['a', 'b', 'c', 'd'],
    attribution: '© <a href="http://osm.org">OpenStreetMap</a>  contributors, © <a href="https://carto.com/">CARTO</a> '
  })
});

map.on('moving moveend zoomend', update);

update();

function update() {
  var projection = map.getProjection();
  var center = map.getCenter(),
    prj = projection.project(center),
    containerPoint = map.coordinateToContainerPoint(center).round();

document.getElementById('coordinate').innerHTML = '<div>' + [
    'Center : [' + center.x.toFixed(5) + ', ' + center.y.toFixed(5) + ']',
    'Projected Coordinate : [' + prj.x.toFixed(5) + ', ' + prj.y.toFixed(5) + ']',
    'ContainerPoint is the screen position in px from northwest of the map container.',
    'ContainerPoint : [' + containerPoint.x + ', ' + containerPoint.y + ']'
  ].join('<br>') + '</div>';
}