bigbluebutton:develop ← sapsDev:palm-rejection-develop-v2.3
opened 01:55PM - 26 Jan 21 UTC
### What does this PR do?
That PR fixes unintentionally drawing (with the han…d on the whiteboard) while using an active pencil (e.g. Apple Pencil).
As mentioned under the issue #11084 the concept of that fix is to add a new button to switch between:
* accepting all kinds of pointer events (finger and pencil touch allowed)
* accepting only pencil events
Therefore the following changes are needed:
* add a new button to the whiteboard toolbar to switch the palm rejection mode
* include a new icon to the BBB Font for the button
* a pull request to the BBB Font Repo is prepared and we can submit it if needed
* add a message to the button and adapt the `locales/en.json`
* we also add german translation to `locales/de.json`, that they are directly available after merging that into BBB
* save the state of the palm rejection mode in the session storage
* add new event handler for pencil and shape
* these handlers are based on the existing event handlers and adapt them to use pointer events. The pointer events are needed to distinguish finger touch, pencil touch and mouse input.
* the handlers accept finger input only if palm rejection is off (finger touch input is allowed)
* add browser sniffing
* BBB provides palm rejection only, if the browser has implemented pointer events
* if not, there is a fallback to the existing event handlers
The mouse input isn't affected by palm rejection but also uses the pointer event handler.
### Closes Issue
closes #11084
### Motivation
Fixing that problem increases the whiteboard user experience significant because the notes aren't impaired by palm and finger artifacts.
### More
* That feature was tested for BBB v2.2.x on Windows, MacOS, Linux, iOS and Android. For the Browsers Chrome, Firefox, Edge, Opera, Yandex, Safari.
* For BBB v2.3 it was tested on Windows, MacOS and iOS with Chrome, Firefox and Safari.
The tests were done by a test protocol and cover using the pencil and the shape tools on the BBB whiteboard with and without palm rejection. At the beginning we developed on BBB v2.2 and switch then to v2.3.
All tests were successfully. In Windows with Firefox it's necessary to set *dom.w3c_pointer_events.dispatch_by_pointer_messages = true* in the Firefox config. By default that parameter is *false*. That is a known bug in Firefox (https://bugzilla.mozilla.org/show_bug.cgi?id=1487509). If that isn't set *true* all touch events are handled as finger touch. So pencils doesn't work with palm rejection enabled.
