It turns out that the timers which repeatedly poll the RTP stats of each video track all run independently of each other and can add up to a small but constant sink of CPU. Meanwhile we can replace these timers with HTMLVideoElement 'resize' event listeners, which is way more efficient and reacts instantly to orientation changes.
A change in a tile's speaking indicator could cause its entire tree of context menu components to re-render, which is expensive. Isolating the behavior subscriptions in their own component avoids this.
On mobile, the ringing status indicator is supposed to display in the header rather than on a tile. The exact layout differs between Android and iOS. To get it right I had to refactor AppBar to use CSS grid templates.
(Also, I changed my mind about the exact ringing data I needed out of CallViewModel - sorry. A little move of the ringtone audio renderer into its own component was necessary to accommodate that.)
I found our code's internal model of ringing a little overgrown (it had superfluous states like 'unknown') and difficult to extend with metadata or callbacks relating to ring attempts. By modeling ringing instead as a stream of ring attempts, where each attempt has an intent, a recipient, and an eventual outcome (accept/decline/timeout), I find it more natural to work with.
This makes room for a future 'try again' callback to allow ringing someone again after a timeout, and also forced me to look for a simpler solution to the duplicate leave sound effects. I exposed the intent of the ringing attempt to the call UI so I can later use it in the header.
By adding viewport-fit=cover to the <meta name="viewport"> header, the page now requests to be displayed edge-to-edge across the entire screen. This gives us control over what we display around camera cut-outs and system navigation UI, if the user agent supports it. I then adjusted the styles of various UI elements to ensure that they still lie within the screen's safe area.
They were not properly being contained to where the MediaView is supposed to appear, causing them to all stack up on the first screen share in the spotlight tile.
6667fc54c0 changed this CSS selector that shows buttons on hover to only target the buttons in the bottom right corner of the spotlight tile, causing the forward/back buttons to stay invisible.
In landscape orientation the button would be buried underneath the footer, which would block interaction with it. This commit changes the footer to not show in cases where a button has been pressed.
Timo and I agreed previously that we should ditch the class pattern for view models and instead have them be interfaces which are simply created by functions. They're more straightforward to write, mock, and instantiate this way.
The code for media view models and media items is pretty much the last remaining instance of the class pattern. Since I was about to introduce a new media view model for ringing, I wanted to get this refactor out of the way first rather than add to the technical debt.
This refactor also makes things a little easier for https://github.com/element-hq/element-call/pull/3747 by extracting volume controls into their own module.
