Can I drag the map with ctrl in Openlayers3?

Question

Exist a way to drag the map when I hold down the Ctrl (control) key?

Normally to drag the map is necessary just hold the left mouse button and move on the map, but I need to drag the map without hold the left mouse button but with the ctrl button. Is possibile?

Answer 1

There is indeed a way to only allow panning while holding ctrl-key. A fully working example can be found in this fiddle: https://jsfiddle.net/mnpq3ufe/

For it to work, you have to disable the existing dragPan interaction in your map init to override/re-add it later on:

interactions: ol.interaction.defaults({
    dragPan: false
})

After that you can create your new customised interaction, which just triggers while ctrl key is pressed, for this we use condition , for more information about conditions and its possibilities you can head over to the OpenLayers APIdocs :

map.addInteraction(new ol.interaction.DragPan({
  condition: function(event) {
    return event.originalEvent.ctrlKey
  }
}));

---

EDIT:

This is just a proof of concept yet and is not fully working, since it snaps into the wrong place when initially starting the drag. Unfortunately I have no time currently to figure everything out right now, but it could probably still help you to get started. Here is the fiddle: https://jsfiddle.net/mnpq3ufe/5/ Basically I am using the pointermove event to recenter the map each time the cursor is moved while holding the ctrl-key:

map.on('pointermove', function(event){
    if(event.originalEvent.ctrlKey){
    var pixelCenter = [map.coordinateToPixelTransform_[4], 
        map.coordinateToPixelTransform_[5]];
    var movedPixels = [pixelCenter[0]-event.pixel[0],
        pixelCenter[1]-event.pixel[1]];
    map.getView().setCenter(map.getCoordinateFromPixel(movedPixels));
  }
});