The relayEvent_ method wraps goog's browser events in our MapBrowserEvent. This allows interactions to deal with real browser events in addition to our emulated events.
This commit refactors the code of the map browser event handler. The changes are the following:
Previously the `handleTouch*_` listener functions handled both `touch*` and `mspointer*` events. With this commit we use per-event type listeners. This duplicates some code (could be avoidable), but makes it easier to introduce mouse/touch/pointer specific treatments in the future.
We now listen to pointermove, pointerup, touchmove and touchend only when needed. In this way we're assured that a `down` event was received (and that `this.down_` is set) when the `up` or `move` listeners are called. This fixes the bug @oterral reported on the mailing list: https://groups.google.com/d/msg/ol3-dev/jR844F7Nlg8/eN9dt4uATK0J.
To avoid problems in browsers that trigger different types of events (e.g. both mouse and pointer events) the `down` listeners unregister the other `down` listeners. For example, the `pointerdown` listener unregisters the `mousedown` and `touchstart` listeners, for ever.
`click` events are fired only if the mouse action button is pressed. This prevents `click` events from being fired when the middle mouse button is used.
Also, without this commit, in Chrome with emulated touch events enabled, double-clicking the map doesn't zoom the map. This is because `ol.BrowserFeature.HAS_TOUCH` is `false` in that environment. The commit fixes it by testing `isMouseActionButton` on mouse devices only.
The map already emits emulated `click` and `dblclick` events on touch and pointer devices. With this commit the map emits emulated `click` and `dblclick` events on mouse devices as well.
On Android (both native browser and Chrome), the handleTouchEnd_
method is sometimes reached in a state where this.down_ is null.
This check protects against this.click_ being called without
an event object. To see this issue, open any example in Android,
and tap the zoom + or - button.
This method is an entry point for getting feature information.
Renderers can use a hit canvas or defer to a layer (source) to
get matching features for a pixel.
For now this is only implemented for vector layers, and it uses
a bbox query because we cannot refine the result because of
missing geometry intersection functions yet.
