OpenLayers示例代码：快照互动
OpenLayers示例代码：快照互动
<!DOCTYPE html>
<html>
<head>
<title>Snap Interaction</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<form id="options-form" automplete="off">
<div class="radio">
<label>
<input type="radio" name="interaction" value="draw" id="draw" checked>
Draw
</label>
</div>
<div class="radio">
<label>
<input type="radio" name="interaction" value="modify">
Modify
</label>
</div>
<div class="form-group">
<label>Draw type </label>
<select name="draw-type" id="draw-type">
<option value="Point">Point</option>
<option value="LineString">LineString</option>
<option value="Polygon">Polygon</option>
</select>
</div>
</form>
<script>
var raster = new ol.layer.Tile({
source: new ol.source.OSM()
});
var vector = new ol.layer.Vector({
source: new ol.source.Vector(),
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'
})
})
})
});
var map = new ol.Map({
layers: [raster, vector],
target: 'map',
view: new ol.View({
center: [-11000000, 4600000],
zoom: 4
})
});
var Modify = {
init: function() {
this.select = new ol.interaction.Select();
map.addInteraction(this.select);
this.modify = new ol.interaction.Modify({
features: this.select.getFeatures()
});
map.addInteraction(this.modify);
this.setEvents();
},
setEvents: function() {
var selectedFeatures = this.select.getFeatures();
this.select.on('change:active', function() {
selectedFeatures.forEach(selectedFeatures.remove, selectedFeatures);
});
},
setActive: function(active) {
this.select.setActive(active);
this.modify.setActive(active);
}
};
Modify.init();
var optionsForm = document.getElementById('options-form');
var Draw = {
init: function() {
map.addInteraction(this.Point);
this.Point.setActive(false);
map.addInteraction(this.LineString);
this.LineString.setActive(false);
map.addInteraction(this.Polygon);
this.Polygon.setActive(false);
},
Point: new ol.interaction.Draw({
source: vector.getSource(),
type: /** @type {ol.geom.GeometryType} */ ('Point')
}),
LineString: new ol.interaction.Draw({
source: vector.getSource(),
type: /** @type {ol.geom.GeometryType} */ ('LineString')
}),
Polygon: new ol.interaction.Draw({
source: vector.getSource(),
type: /** @type {ol.geom.GeometryType} */ ('Polygon')
}),
getActive: function() {
return this.activeType ? this[this.activeType].getActive() : false;
},
setActive: function(active) {
var type = optionsForm.elements['draw-type'].value;
if (active) {
this.activeType && this[this.activeType].setActive(false);
this[type].setActive(true);
this.activeType = type;
} else {
this.activeType && this[this.activeType].setActive(false);
this.activeType = null;
}
}
};
Draw.init();
/**
* Let user change the geometry type.
* @param {Event} e Change event.
*/
optionsForm.onchange = function(e) {
var type = e.target.getAttribute('name');
var value = e.target.value;
if (type == 'draw-type') {
Draw.getActive() && Draw.setActive(true);
} else if (type == 'interaction') {
if (value == 'modify') {
Draw.setActive(false);
Modify.setActive(true);
} else if (value == 'draw') {
Draw.setActive(true);
Modify.setActive(false);
}
}
};
Draw.setActive(true);
Modify.setActive(false);
// The snap interaction must be added after the Modify and Draw interactions
// in order for its map browser event handlers to be fired first. Its handlers
// are responsible of doing the snapping.
var snap = new ol.interaction.Snap({
source: vector.getSource()
});
map.addInteraction(snap);
</script>
</body>
</html>
说明：
OpenLayers示例代码：快照互动
