[Xournal-devel] Xournal presentation mode

[Axel K. <ax...@gm...>]

Dear list,

attached is a patch that adds presentation mode capabilities to Xournal. It
opens a second window in full screen mode on another monitor with the zoom
level fixed to one. The standard window on the monitor with the pen enabled
is zoomable. This is intended to be used as teaching tool as replacement to
a blackboard in larger lecture halls. When simply mirroring the monitors I
figured one has to write quite big on the pen enabled monitor to be able to
write cleanly and thus wouldn't fit much content on a screen. With this
mode, one can zoom in on the control monitor to comfortably write cleanly,
while the studends see the whole page, also comfortable as it is projected
to a big overhead screen.

It is an ugly hack I do not request to be applied, but I want it to serve
as discussion base how to make this in a clean and portable way.

The main issue is that many calls to the canvas are direct, so it needed to
patch all the places that interact with the canvas at all. Since there is
also discussion to be able to replace the canvas implementation, would it
be a good idea to encapsulate a little more, to have "xo-canvas" as
pseudo-object class, that all places call, and where it could decide to
actually draw on two canvases, or to change the canvas implementation with
only having to alter a few places?

The second issue with this patch is more simpler pragmatic hacking. I
didn't bother to add options in the menu, it's simply another binary to be
called that will fail if it cannot detect two monitors. But thats less an
issue to add, when the former things are cleaned up. Some of the zooming
stuff is a little odd, since I didn't fully understand the code in
interaction with PDF, I changed it so the resolution looks good on the
presentation monitor, which is the important thing in this mode

Kind regards, Axel