OpenLayer学习之自定义测量控件

.tooltip {
 position: relative;
 background: rgba(0, 0, 0, 0.5);
 border-radius: 4px;
 color: white;
 padding: 4px 24px 4px 8px;
 opacity: 0.7;
 white-space: nowrap;
}
.tooltip-measure {
 opacity: 1;
 font-weight: bold;
}
.tooltip-static {
 background-color: #ffcc33;
 color: black;
 border: 1px solid white;
}
.tooltip-measure:before,
.tooltip-static:before {
 border-top: 6px solid rgba(0, 0, 0, 0.5);
 border-right: 6px solid transparent;
 border-left: 6px solid transparent;
 content: "";
 position: absolute;
 bottom: -6px;
 margin-left: -7px;
 left: 50%;
}
.tooltip-static:before {
 border-top-color: #ffcc33;
}
.ol-popup-closer {
  text-decoration: none;
  position: absolute;
  top: 4px;
  right: 8px;
  color: red;
}
.ol-popup-closer:after {
  content: "";
}
/*MeasureTool*/

.MeasureTool{
 position: absolute;
 top: 2.0em;
 right: 5em;
 text-align: left;
 padding: 0;
}
.MeasureTool .ulbody{
 display: none;
}
.MeasureTool.shown .ulbody{
 display: block;
}
.ulbody li input:focus, .ulbody li input:hover {
 background-color: white;
 color: blue;
 font-weight: bold;
}
.MeasureTool ul {
 padding: 0;
 list-style: none;
 margin: 0;
}
.MeasureTool ul li{
 text-align: center;
}
.MeasureTool>ul>li>input{
 background-image: url('data:image/png;base64,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') /*logo.png*/;
 background-position: center center;
 background-repeat: no-repeat;
}
.MeasureTool input[type="button"]{
 background-color: rgba(255, 255, 255, 0.4);
 width: 60px;
 height: 26px;
 border: 0;
}
.MeasureTool .ulbody li{
 border-top: 1px solid rgba(221, 221, 221, 0.4);
}

/**
 * OpenLayers 3 MeasureTool Control.
 * See [the examples](./examples) for usage.
 * @constructor
 * @extends {ol.control.Control}
 * @param {Object} opt_options Control options, extends olx.control.ControlOptions adding:
 *               **`tipLabel`** `String` - the button tooltip.
 */
//构造函数
ol.control.MeasureTool = function(opt_options) {

 var options = opt_options || {};

 this.sphereradius = options.sphereradius "button";
 ulheader.appendChild(inputMeasure);

 var ulbody = document.createElement('li');
 this.panel.appendChild(ulbody);

 var html = '';
 html += '<ul class="ulbody">';
 html += '<li><input type="button" value="Line"></li>';
 html += '<li><input type="button" value="Area"></li>';
 html += '<li><input type="checkbox" value="no"></li>';
 html += '</ul>';
 ulbody.innerHTML = html;

 var this_ = this;

 inputMeasure.onmouseover = function(e) {
  this_.showPanel();
 };
 inputMeasure.onclick = function(e) {
   e = e || window.event;
   this_.showPanel();
   e.preventDefault();
 };

 var lis = ulbody.getElementsByTagName("li");

 this.sourceMesure = new ol.source.Vector();
 this.vectorMesure = new ol.layer.Vector({
   source: this.sourceMesure,
  style: new ol.style.Style({
   fill: new ol.style.Fill({
    color: 'rgba(255, 255, 255, 0.2)'
   }),
   stroke: new ol.style.Stroke({
    color: '#ffcc33',
    width: 2
   }),
   image: new ol.style.Circle({
    radius: 7,
    fill: new ol.style.Fill({
     color: '#ffcc33'
    })
   })
  })
 });

 //type length or area
 var typeSelect={};
 //Line start
 lis[0].onclick = function(e) {
  typeSelect.value = 'length';
  typeSelect.check = lis[2].getElementsByTagName("input")[0].checked;
  this_.mapmeasure(typeSelect);
 };
 //Area start
 lis[1].onclick = function(e) {
  typeSelect.value = 'area';
  typeSelect.check = lis[2].getElementsByTagName("input")[0].checked;
  this_.mapmeasure(typeSelect);
 };

 this_.panel.onmouseout = function(e) {
   e = e || window.event;
   if (!this_.panel.contains(e.toElement || e.relatedTarget)) {
     this_.hidePanel();
   }
 };

 ol.control.Control.call(this, {
   element: element,
 });

};
//继承
ol.inherits(ol.control.MeasureTool, ol.control.Control);

ol.control.MeasureTool.prototype.mapmeasure = function(typeSelect) {
  var source = this.sourceMesure;
  var vector = this.vectorMesure;
 var wgs84Sphere = new ol.Sphere(this.sphereradius);

 var sketch;
 var helpTooltipElement;
 var measureTooltipElement;
 var measureTooltip;

 var map = this.getMap();
 map.addLayer(vector);

 map.getViewport().addEventListener('mouseout', function() {
  helpTooltipElement.classList.add('hidden');
 });

 var draw; // global so we can remove it later

 var formatLength = function(line) {
  var length;
  if (typeSelect.check) {
   var coordinates = line.getCoordinates();
   length = 0;
   var sourceProj = map.getView().getProjection();
   for (var i = 0, ii = coordinates.length - 1; i < ii; ++i) {
    var c1 = ol.proj.transform(coordinates[i], sourceProj, 'EPSG:4326');
    var c2 = ol.proj.transform(coordinates[i + 1], sourceProj, 'EPSG:4326');
    length += wgs84Sphere.haversineDistance(c1, c2);
   }
  } else {
   var sourceProj = map.getView().getProjection();
   var geom = /** @type {ol.geom.Polygon} */(line.clone().transform(
     sourceProj, 'EPSG:3857'));
   length = Math.round(geom.getLength() * 100) / 100;
   // length = Math.round(line.getLength() * 100) / 100;
  }
  var output;
  if (length > 100) {
   output = (Math.round(length / 1000 * 100) / 100) +
     ' ' + 'km';
  } else {
   output = (Math.round(length * 100) / 100) +
     ' ' + 'm';
  }
  return output;
 };

 var formatArea = function(polygon) {
  if (typeSelect.check) {
   var sourceProj = map.getView().getProjection();
   var geom = /** @type {ol.geom.Polygon} */(polygon.clone().transform(
     sourceProj, 'EPSG:4326'));
   var coordinates = geom.getLinearRing(0).getCoordinates();
   area = Math.abs(wgs84Sphere.geodesicArea(coordinates));
  } else {
   var sourceProj = map.getView().getProjection();
   var geom = /** @type {ol.geom.Polygon} */(polygon.clone().transform(
     sourceProj, 'EPSG:3857'));
   area = geom.getArea();
   // area = polygon.getArea();
  }
  var output;
  if (area > 10000) {
   output = (Math.round(area / 1000000 * 100) / 100) +
     ' ' + 'km<sup>2</sup>';
  } else {
   output = (Math.round(area * 100) / 100) +
     ' ' + 'm<sup>2</sup>';
  }
  return output;
 };

 var popupcloser = document.createElement('a');
 popupcloser.href = 'javascript:void(0);';
 popupcloser.classList.add('ol-popup-closer');

 function addInteraction() {
  var type = (typeSelect.value == 'area' "touchstart", function(event) {
      scrollStartPos = this.scrollTop + event.touches[0].pageY;
    }, false);
    elm.addEventListener("touchmove", function(event) {
      this.scrollTop = scrollStartPos - event.touches[0].pageY;
    }, false);
  }
};

/**
 * @private
 * @desc Determine if the current browser supports touch events. Adapted from
 * https://gist.github.com/chrismbarr/4107472
 */
ol.control.MeasureTool.isTouchDevice_ = function() {
  try {
    document.createEvent("TouchEvent");
    return true;
  } catch(e) {
    return false;
  }
};

<script src="/UploadFiles/2021-04-02/measuretool.js">

2、声明控件


new ol.control.MeasureTool( {sphereradius : 6378137}),


其中的参数sphereradius 是用来支持geodesic测量设置球体半径的，可根据不同的模型设置不同的半径大小，默认大小为6378137，在引入时也可以不传入该参数。
NOTE：测量工具中的checkbox选中为使用geodesic测量，未选中为不使用geodesic测量，默认为未选中。
四、总结
通过这几天的研究我发现如果要实现自定义控件，里面有部分函数我们不需要改动，在构造函数那一部分我们需要创建自己定义的标签，其他后面最后的几个函数是不需要改动的，待下次继续完善