With this change, a client (i.e., display driver) can register
a wakeup signal handler to be notified on the arrival of new data to
capture. The signal is delivered only when the client has stopped
capturing. The client propagates this condition to the server using
the new 'capture_stopped' RPC call.
This change in principle enables a display driver to suspend its
periodic mode of operation after a few frames without capturing any
new data. As the first driver, the fb_sdl driver has been adapted to
the new protocol. This change not only eliminates the driver's CPU
load when idle, it also reduces the latency of sporadic output
because the response to such GUI updates is no longer bound by a
fixed periodic interval.
Issue #5344
This patch enhances the Capture::Connection::Screen such that the
bounding box of the affected pixels can be tracked by the caller,
which can use this information to adjust its behavior to the
activity/inactivity of the capture server.
Issue #5344
This patch adds the physical screen size as argument to the
Capture::Session::buffer RPC function, which allows drivers to
propagate DPI information to the GUI server. While changing the
the interface, the patch replaces the former use of C++ exceptions
by a result type. The 'Buffer_result' is handled transparently by the
Capture::Connection. The client.h code is now integrated in
connection.h.
Issue #5344
