openlayers-3 - ol3/Openlayers3 : change radius of circle when zoomed

Question

我有一个当前定义为样式的矢量图层:

var styles = new ol.style.Style({
image: new ol.style.Circle({
  radius: 4,
  fill: new ol.style.Fill({color: 'red'}),
  stroke: new ol.style.Stroke({color: 'black', width: 1})
})

我希望半径根据 map 缩放级别动态变化 - 例如:

半径:(缩放/2)+1

我该怎么做？

更新: Jonatas 的评论帮助我朝着正确的方向前进。我最终使用了以下内容:

map.getView().on('change:resolution', function(evt) {
  var zoom = map.getView().getZoom();
  var radius = zoom / 2 + 1;

  var newStyle = new ol.style.Style({
      image: new ol.style.Circle({
      radius: radius,
      fill: new ol.style.Fill({color: 'red'}),
      stroke: new ol.style.Stroke({color: 'black', width: 1})
    })
  })
  vectorLayer.setStyle(newStyle);
});

Answer 1

您可以收听分辨率更改:

map.getView().on('change:resolution', function(evt){
    //according to http://openlayers.org/en/v3.6.0/apidoc/ol.View.html
    // I think this is not true for any scenario
    //40075016.68557849 / 256 / Math.pow(2, 28) = 0.0005831682455839253

    var resolution = evt.target.get(evt.key),
        resolution_constant = 40075016.68557849,
        tile_pixel = 256;

    var result_resol_const_tile_px = resolution_constant / tile_pixel / resolution;

    var currentZoom = Math.log(result_resol_const_tile_px) / Math.log(2);
    console.info(currentZoom, resolution);

    //now find your features and apply radius
    feature.getStyle().getGeometry().setRadius(radius);
});

请注意，我正在将分辨率转换为缩放，但这只是一种好奇。您可以摆脱它并根据分辨率设置半径。