[GIS] How to get an existing feature’s rotation angle in OpenLayers 3

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I created two external controls for my OpenLayers 3 map: Rotate Left and Rotate Right.
I already stored the last dragged/clicked feature in a global variable, yet I'm struggling to retrieve the actual rotation of the feature to "add" or "substract" degrees to it.

Here is what the code of my "Rotate Right" button looks like:

var evt = lastEvent;
if (evt == "") {
    return false;
} else {
    var coordX = evt.coordinate[0];
    var coordY = evt.coordinate[1];

    var feature = map.forEachFeatureAtPixel(evt.pixel,
        function(feature, layer) {
            return feature;
        });

    var layer = map.forEachFeatureAtPixel(evt.pixel,
        function(feature, layer) {
            return layer;
        });

    // This is where I need to get the feature's rotation value.
    var rotation = Math.random() * 10 + 1;
    var origin = new ol.geom.Point(coordX, coordY);
    feature.setStyle(new ol.style.Style({
        image: new ol.style.Icon( /** @type {olx.style.IconOptions} */ ({
            anchor: [0.5, 0.5],
            rotation: rotation,
            anchorXUnits: 'fraction',
            anchorYUnits: 'fraction',
            src: 'https://cdn4.iconfinder.com/data/icons/pictype-free-vector-icons/16/home-128.png'
        }))
    }));
}

I've been browsing through the API documentation and the examples but I can't seem to find a way to access the feature's rotation value once it's already drawn on the layer.

Best Answer

I don't if the reason that you couldn't find anything in the documentation, was because you didn't un-clicked the "Stable only" in the upper right corner of the API documentation.

Try this:

var _feature; // your feature
var _style = _feature.getStyle();
var _imagestyle = _style.getImage();
var rotation = _imagestyle.getRotation();

I haven't testet it, but give it a try.

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