Method _getResolution

src/mapboxgl/overlay/MapvLayer.js:116–123

()

  }

  _getResolution() {
    var bounds = this.map.getBounds();
    var dw = bounds.getEast() - bounds.getWest();
    var rect = this.map.getCanvas().getBoundingClientRect();
    var resolutionX = dw / rect.width;
    // 一个像素是多少米
    return getMeterPerMapUnit('DEGREE') * resolutionX;
  }

  _getCenterPixel() {
    return this.map.project(new mapboxgl.LngLat(0, 0));