This commit removes an incorrect assertion from the modify interaction, which currently triggers when adding vertices to a line string. A new condition is added to the `if` statement to prevent a compilation error. In practice, `depth` and `segmentDataMatch.depth` are either both defined or both undefined.
By default, zooming in or out zooms using the mouse's location
as an anchor, which makes it possible to navigate the map
using scrolling only, and makes zooming in more intuitive.
This commit adds a new useAnchor option to the MouseWheelZoom
interaction. It is enabled by default, which changes nothing
to the current behavior of the interaction. When disabled,
the interaction stops registering its lastAnchor_ value. This
turns the zoom into a very basic one, that zooms to the center
of the screen.
To use the map center zoom, set the useAnchor option to
false when creating the MouseWheelZoomInteraction, or use its
setMouseAnchor function.
This commit adds an `extend` method to the draw interaction. This method makes it possible to extend (continue drawing) an existing line string feature. It only works on line string features, where this functionality makes the most sense.
Here's an example on how to use `extend`:
```js
var vectorSource = vectorLayer.getSource();
vectroSource.removeFeature(feature);
drawInteraction.extend(feature);
```
This allows features to be moved around the map. It works much like the Modify interaction, however it's significantly simpler. It uses the geometry's underlying `translate` function.
The previous approach did not work on mobile devices where no `pointermove`
event is sent except from dragging.
Logic now is: Upon vertex creation due to `pointerdown` we will ignore
the next `singleclick` event unless there is a `pointerdrag` event, which will
not lead to a `singleclick` event following the vertex creation.
Resolves#3935
* Skipped features need to be hit-detected on unmanaged layers.
* updateWhileAnimating and updateWhileInteracting are recommended to
achieve the same instant visual feedback that ol.FeatureOverlay had.
