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.
gtk_widget_set_double_buffered is now deprecated, and we don't support
non-double-buffered widgets. This means that under normal circumstances,
paints are never outside of a begin_paint / end_paint sequence, which
natively-double-buffered backends like Wayland can't possibly support.
Weston releases buffers almost immediately after they're done, which
means that GTK+ doesn't use a temporary surface and instead paints
directly onto the SHM backing store that Weston will use.
Normally, after painting to the temporary surface, GTK+ *replaces*
the existing backing surface with CAIRO_OPERATOR_SOURCE. However,
if we immediately paint to the backing surface, it might have junk
from the last paint in it. So clear out the backing surface whenever
somebody calls begin_paint_region().
Maybe we should just always use the temporary surface like the X11
codepath, since that prevents us from having to do weird things like
this, but oh well.
wl_surfaces can't switch roles, so destroying the xdg_surface but not
the wl_surface means that we could get an error when trying to re-map
the surface.
We could fix this by not destroying the xdg resource and only do it at
finalization time, but it's just as easy to just create a new wl_surface.
Since the xdg roles are a special case of the surface, some compositors
like Weston destroy them automatically when the wl_surface is destroyed.
Thus, we need to destroy these first.
The Wayland compositor is completely allowed to send us configure
events for the same size, and this validly happens if we're changing
states. Fizzle these out.
Having the same, usable, default appearance acroll platforms
trumps having a more-or-less working native theme. The default
will be Adwaita on all platforms. The native ms-windows theme
is of course still available.
Weston numbers its touch sequences ids starting from 0, thus simply
setting the GtkEvents touch.sequence to the touch id value typically
causes gdk_event_get_event_sequence to return NULL. Unfortunately this
confuses other parts of GDK.
As both weston & mutter keep the sequence id between 0..max_dev_touches
-1 simply use + 1 to keep the id > 0. While this isn't entirely correct
(compositor could send -1 as the touch id), this keeps the touch id in
gtk tied to the touch id from weston which is useful for debugging. A
more thorough solution could be done when it turns out this is an issue
in practise
https://bugzilla.gnome.org/show_bug.cgi?id=731371
There are plans to add session-dependent defaults to GSettings
(based on the newly standardized XDG_CURRENT_DESKTOP); until
then, the WM uses a different schema for its button-layout
setting in classic mode. So for the time being, do the same
and pick the alternative schema when XDG_CURRENT_DESKTOP
indicates that we are in a classic session.
(It's not pretty, but hopefully won't be with us for too long ...)
https://bugzilla.gnome.org/show_bug.cgi?id=731273
Pick up the setting from the org.gnome.desktop.wm.preferences schema
if available. It is slightly more involved than other settings, as
the actual button names used in the schema differ from the ones we
use, so we need an additional translation step.
https://bugzilla.gnome.org/show_bug.cgi?id=731273
When the pointer cursor is updated on CSW, lookup for either a device
cursor, or a global one. It would previously lookup for windows with
a global cursor, and then check if it had a device cursor, which would
skip windows with only device cursors set, and unexpectedly set the
global cursor.
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.
All the globals we care about should appear before doing anything
else, up-front, so a single round-trip after adding the registry
should be more than enough.
Since you can't take grabs on unmapped windows, GtkMenu takes a grab on
the menu in a convoluted way: it first grabs another window, shows the
menu window, and then transfers the grab over to the GtkMenu widget.
For normal menubars, this is perfectly fine, as the first window it grabs
is our toplevel, and that gets picked up in our transient path. For
GtkMenuButton or other spurious uses of gtk_menu_popup, it creates a new
temporary input-only window which it takes the grab on, known as the "grab
transfer window". Since this window isn't a transient-for of our new menu
widget window, the grab isn't noticed when we go to show it, and thus the
menu ends up as a new toplevel.
Add a special hack to GtkMenu and the Wayland backend which lets us notice
this "grab transfer window", and include it in our grab finding path.
It's sort of terrible to have to hack up the widgets instead of just the
backend, but the alternative would be an entirely new window type which is
managed correctly by GDK. I don't want to write that.
Wayland's mechanism tells us all of our new states, rather than
telling us which ones were added and removed. Add a new private
interface so that we can simply specify the new states as a
bitfield directly rather than having to compute which ones were
added and removed.
Rendering doesn't do much about clipping drawing operations to the window shape,
although invalidation applies the shape to every window, leaving possibly trails
of "overrendered" content. So ensure the shape portions get invalidated too when
the window is moved/resized.
https://bugzilla.gnome.org/show_bug.cgi?id=729095
