The native WebSocket is in a much better position to do queue
management than us. We also failed to check the return value and
set up a timer, causing stalls.
This gets us in sync with websockify as of 40238b00.
We don't have to check for _display or context here since this is a
private function which is never called under such circumstances. This
solves problems caused by display.get_context() which was previously
removed in e549ae074f.
The old default was to ask for the maximum compression level. This
is against the recommendations in libvncserver/tight.c due to excessive
CPU load. It also causes Vino 3.8.1 (still shipped with Ubuntu 16.04
LTS) to prefer the blurry JPEG compression too much - e.g. red text on
the default background in MATE terminal becomes almost unreadable.
The new default is the recommended compression level for low-color
workloads, according to libvncserver source. Also, it is the maximum
compression level that doesn't trigger the Vino bug with red text in
most cases.
Fixes issue #737.
Do all rendering to a hidden canvas and then copy over the finished
frame to the visible canvas once everything is done. This simplifies
things and solves some bugs as we can retain a copy of the entire
frame buffer.
Supports server configurations that might prefer wss:// connections
on the default port, then proxies them through the web server to the
VNC server.
This proxy configuration is helpful on servers using self-signed
certificates. Accessing the https://host/vnc_auto.html page and
adding an exception for that host is sufficient to also satisfy the
wss://host/ request, unlike requests to wss://host:port/ which
may require an extra certificate exception.
RFB's _fail function logs the error, disconnects the session and sets
disconnect_reason. The disconnect_reason is upon disconnection sent to
the user interface. It is thus not suitable for including error details
that aren't user friendly. The idea is that you will look in the
browser console for a full log with details of the error.
RFB._fail() can be called at any time in any state, it is not certain
that we will get a close event on the socket since the socket might not
be open. This caused us to hit the disconnect timeout in such cases.
Fixes issue #678
For example, previously if the user typed in illegal characters in the
port field, no error would be displayed in the interface and the page
would stop at "connecting".
There is a specific event for when an image has finished loading,
so trigger on that rather than polling. The polling interval of
requestAnimationFrame() can also be very large.
The callers don't need to concern themselves with how images are
rendered, so hide the details behind the API. This also avoids
exposing the render queue.
Mouse wheel event handling has now been standardised and has broad
support. Use this event rather than the older, non-standard ones.
At the same time fix up support for horisontal mouse wheel events.
