Traditionally, the way painting was done in GTK+ was with the
"expose-event" handler, where you'd use GDK methods to do drawing on
your surface. In GTK+ 2.24, we added cairo support with gdk_cairo_create,
so you could paint your graphics with cairo.
Since then, we've added client-side windows, double buffering, the paint
clock, and various other enhancements, and the modern way to do drawing
is to connect to the "draw" signal on GtkWidget, which hands you a
cairo_t. To do double-buffering, the cairo_t we hand you is actually on
a secret surface, not the actual backing store of the window, and when
the draw handler completes we blit it into the main backing store
atomically.
The code to do this is with the APIs gdk_window_begin_paint_region,
which creates the temporary surface, and gdk_window_end_paint which
blits it back into the backing store. GTK+'s implementation of the
"draw" signal uses these APIs.
We've always sort-of supported people calling gdk_cairo_create
"outside" of a begin_paint / end_paint like old times, but then you're
not getting the benefit of double-buffering, and it's harder for GDK to
optimize.
Additionally, newer backends like Mir and Wayland can't actually support
this model, since they're based on double-buffering and swapping buffers
at various points in time. If we hand you a random cairo_t, we have no
idea when is a good time to swap.
Remove support for this.
This is technically a GDK API break: a warning is added in cases where
gdk_cairo_create is called outside of a paint cycle, and the returned
surface is a dummy that won't ever be composited back onto the main
surface. Testing with complex applications like Ardour didn't produce
any warnings.
This avoids a bunch of policy problems with deciding how to lay
out the window menu under different WMs.
For now, we use the special event _GTK_SHOW_WINDOW_MENU, but we
hope to have this standardized in wm-spec quite soon, as KDE wants
it as well.
It seems that some backends implemented get_root_origin wrong
and returned the client window coordinates, not the frame window
coordinates. Since it's possible to implement generically for all
windows, let's do that instead of having a separate impl vfunc.
And the counterpart to unmaximize when dragging a maximized window, if
touch devices aren't going to use EWMH moveresize, having this one at least
makes things feel a bit less awkward.
https://bugzilla.gnome.org/show_bug.cgi?id=709914
Sadly, EWMH moveresize mechanism can't work with touch devices for two
reasons:
1) As a mutter implementation detail, the device is queried in order
to check whether the dragging button is still pressed. Touch devices
won't report the button 1 being pressed through pointer emulation.
2) Even bypassing that check, on X11 touch events are selected prior
to sequences being started, either through XISelectEvents or
XIGrabTouchBegin, no late registering through active grabs is allowed,
as WMs do on reaction to EWMH moveresize messages.
So for the time being, make touch devices fallback on emulated window
dragging, which at least allows for moving windows.
https://bugzilla.gnome.org/show_bug.cgi?id=709914
We have a hack in the XSETTINGS code to substitute gtk-xft-dpi
with gdk-unscaled-dpi unless the screen has a fixed window scale,
in which case we just use gtk-xft-dpi.
But if the screen is changed to have a fixed window scale, then
the substituted value of gdk-unscaled-dpi will stick around until
the next (coincidental) change to XSETTINGS. To fix this, force
an immediate reread of the XSETTINGS property when
gdk_x11_display_set_window_scale() is used.
https://bugzilla.gnome.org/show_bug.cgi?id=725754
Instead of destroying the surface in the backend if this is
unable to resize, let the core code do it, and do it properly.
Based on a patch by Benjamin Otte.
https://bugzilla.gnome.org/show_bug.cgi?id=725172
This setting will let us keep traditional appearance
of dialogs on platforms where this is expected.
The new setting is called gtk-dialogs-use-header, backed
by the Gtk/DialogsUseHeader xsetting.
The EWMH defines _NET_WM_MOVERESIZE_SIZE_KEYBOARD and
_NET_WM_MOVERESIZE_MOVE_KEYBOARD for operations that are not
initiated by a button-press event. Allow using these by passing
a button of 0 to gdk_window_begin_move/resize_drag.
fvwm seems to have problems keeping _NET_WORKAREA in sync with
the number of desktops. Instead of reading garbage, silently use
the full screen as workarea for desktops that are not covered
by the _NET_WORKAREA property.
https://bugzilla.gnome.org/show_bug.cgi?id=698248
