如何更改OpenLayers中的图像颜色3

Question

我是openlayers的新手3。我以图像的形式显示点，但我想动态更改图像的颜色。在openlayers3中可能会或其他设施(例如openlayers中的画布(3？

var iconStyle = new ol.style.Style({ 
    image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
         anchor: [0.5, 46], 
         anchorXUnits: 'fraction', 
         anchorYUnits: 'pixels', 
         src: 'data/icon.png' 
    })) 
}); 

Answer 1

以图标颜色为起点，在其中使用透明的png带有 ol.Color选项具有多种颜色点，我尝试更改这样的颜色而没有成功...

var london = new ol.Feature({
  geometry: new ol.geom.Point(ol.proj.fromLonLat([-0.12755, 51.507222]))
});
london.setStyle(new ol.style.Style({
  image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
    color: '#ff0000',
    crossOrigin: 'anonymous',
    src: 'https://openlayers.org/en/v4.1.1/examples/data/dot.png'
  }))
}));
var vectorSource = new ol.source.Vector({
  features: [london]
});
var vectorLayer = new ol.layer.Vector({
  source: vectorSource
});
var rasterLayer = new ol.layer.Tile({
  source: new ol.source.TileJSON({
    url: 'https://api.tiles.mapbox.com/v3/mapbox.geography-class.json?secure',
    crossOrigin: ''
  })
});
var map = new ol.Map({
  layers: [rasterLayer, vectorLayer],
  target: document.getElementById('map'),
  view: new ol.View({
    center: ol.proj.fromLonLat([2.896372, 44.60240]),
    zoom: 3
  })
});
map.on('singleclick', function (event) { // Use 'pointermove' to capture mouse movement over the feature 
  map.forEachFeatureAtPixel(event.pixel, function (feature, layer) {
    /* Get the current image instance and its color */
    var image = feature.getStyle().getImage();
    console.log(image.getColor());
    
    /* Color gets stored in image.i, but there's no setter */
    console.log(image.i);
    
    /* Trying to force the color change: */
    image.i = [0, 255, 0, 1];
    
    /* Dispatch the changed() event on layer, to force styles reload */
    layer.changed();
    
    console.log(image.getColor()); // Logs new color, but it doesn't work...
    
  });
});

<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.1.1/build/ol.js"></script>
<div id="map" class="map"></div>

查看如何检索这样的图标颜色：

var image = feature.getStyle().getImage(),
    color = image.getColor(); // returns [R, G, B, alpha]

但是没有setColor()方法，因此无法在运行时更改颜色...

---

编辑：再次查看您的问题和代码，我注意到您永远不会为图标设置颜色，所以也许您真的不想真正更改应事件的颜色，但只是 set 颜色。如果那是您想要的，那很容易：

var iconStyle = new ol.style.Style({ 
     image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
         anchor: [0.5, 46], 
         anchorXUnits: 'fraction', 
         anchorYUnits: 'pixels', 
         src: 'data/icon.png',
         color: '#ff0000' // allows HEX as String or RGB(a) as Array
     })) 
});

请参阅：http：//openlayers.org/en/latest/apidoc/ol.style.icon.icon.html