This reverts commit b875572f2a.
Apps like Abiword, gnumeric and gnome-chess, and toolkits like
ClutterGTK were all using this for various purposes, and this made them
break. Bring back this feature for now.
It still won't work under Wayland.
Apps had quite a bit of difficulty getting used to the new rules.
While we weren't expecting anything too deadly, it seemed that
gnumeric and Abiword both used gdk_cairo_create like this.
If a window both has an impl and its impl_window is of type offscreen,
that must mean that it is the offscreen window, and the impl window is
itself. We can reduce the indirection here and make it more clear.
Since the Win32 code never actually called InvalidateRgn or used the
Win32 update area at all, that meant the only thing that could possibly
invalidate the window was the Win32 window manager as part of scrolling
or resizing, which would also send it a WM_PAINT message.
But the WM_PAINT handling called BeginPaint / EndPaint, which clears the
update area completely! We also draw out-of-band, not directly when
handling WM_PAINT, so there's no way that the update area inside the
Win32 WM would match our local one.
There is no possible way that this queue_antiexpose implementation could
do anything. Remove it.
We removed the parameter from callers and from the implementation, but
not from the signature up top. I didn't notice because the branch I was
working on removed the signature entirely.
This code is only called with the current paint region as its argument.
Instead of having to copy it and do a no-op intersect against itself,
just use the current paint directly.
cairo_surface_create_for_rectangle takes a ref on the parent surface,
so we need to drop ours.
Rename get_window_surface to ref_window_surface to make the code more
clear and to stop this error from happening again.
Previously, each begin_paint_region added to a stack of current paints,
and when end_paint was called, the paint was popped off of the stack and
the surface was composited into the parent paint surface.
However, the code was broken in the case of a backend like Wayland which
didn't keep track of nested calls and simply wiped and returned the
native impl backing surface every time.
Since this feature is flat out unused by GTK+ and we don't want to
really support tricksy things like these for other clients, just remove
the feature. If somebody does call begin_paint_region more than once,
warn and return without doing anything.
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
