... and a delay before the screenshot.
Until now, there was only delay before selection, which I changed in
commits d9cd4b61bc and 614bcf6d0a. Actually a delay before selection may
also be useful, for instance when you use a tablet without keyboard (no
alt-tab possible) and the window/area you wish to capture is behind GIMP
window. Then you'd want to interact with the desktop with the pointer
before the cursor changes for selection interaction.
I add some logics so that the selection delay doesn't show when it is
unecessary (for instance for full-screen screenshot, or when the window
screenshot is based on the active window, not click selection, like with
GNOME shell API).
Delay should indeed happen before root and window screenshots, but must
happen in-between region selection and region screenshot.
One can notice that the logics is different for Windows screenshot in
X11. The reason is that X11 window screenshot has an additional window
selection step (and therefore delay must happen in between selection and
actual screenshot). Window screenshot in Wayland doesn't have this step
and simply screenshots whatever is the currently active Window.
Add color management options to the screenshot plug-in:
By default, it tries to tag the image with the monitor profile;
alternatively, there is an option to convert the image to sRGB.
This works mostly fine on *one* monitor given its profile is
configured correctly. With more than one monitor, funny things happen
depending on the platform and on what we are shooting (window, screen,
area). There are some FIXMEs left in the code.
Add error reporting to all screenshot backends, but only really use it
in the gnome-shell backend: check all DBus calls for errors instead of
crashing.
Also fix detection if gnome-shell is running: just creating the
GDBusProxy always succeeds, so call org.freedesktop.DBus.Peer.Ping
on the newly created proxy.
Some more abstraction in the screenshot plug-in, now allows for
runtime backend selection. Add stubs for the gnome-shell backend,
registers itself as unavailable because it's still unimplemented.
