We now rely on toplevels receiving and forwarding all the events
the windowing should be able to handle. Event masks are no longer a
way to determine whether an event is deliverable ot a widget.
Events will always be delivered in the three captured/target/bubbled
phases, widgets can now just attach GtkEventControllers and let those
handle the events.
gtk_snapshot_pop() => removed
gtk_snapshot_pop_and_append() => gtk_snapshot_pop()
So now there is no way to get a rendernode out of the snapshotting API
until you gtk_snapshot_finish().
Add a new ::measure vfunc similar to GtkCssGadget's that widget
implementations have to override instead of the old get_preferred_width,
get_preferred_height, get_preferred_width_for_height,
get_preferred_height_for_width and
get_preferred_height_and_baseline_for_width.
And with it, gtk_widget_get_visual() and gtk_widget_set_visual() are
gone.
We now always use the RGBA visual (if available) and otherwise fall back
to the system visual.
That would imply the pixelcache monitors the style context for changes
and it doesn't do that.
Its only use case was opacity checks, so add
gtk_pixel_cache_se_is_opaque() instead.
The viewport itself doesn't move, so we cannot use it as the pixel
cache's background. Use the bottommost using element instead, which is
the viewport's child.
This might need adaptations in themes as we want the backgroud to be
opaque to speed up pixel cache performance.
GtkViewport currently tries to draw a background over the bin window.
The feature is a bit broken at the moment, as it does not take into
account padding that might have been set on the GtkViewport, but in
general it does not seem very useful, and goes somewhat against the CSS
box model where every widget/gadget is responsible to draw its own
background. For a fix, we could either have the viewport gain a "bin"
gadget, or we could stop drawing the background.
As it isn't clear that there are any users of this feature, stop drawing
the background; a client can achieve the same effect by drawing the
background on the widget inside the viewport itself.
These days exposure happens only on the native windows (generally the
toplevel window) and is propagated down recursively. The expose event
is only useful for backwards compat, and in fact, for double buffered
widgets we totally ignore the event (and non-double buffering breaks
on wayland).
So, by not setting the mask we avoid emitting these events and then
later ignoring them.
We still keep it on eventbox, fixed and layout as these are used
in weird ways that want backwards compat.
Translate shadow != None into the FRAME style class.
This doesn't change the style classes used for drawing,
it only sets the style class permanently instead of
saving and restoring in draw().
https://bugzilla.gnome.org/show_bug.cgi?id=732256
Since gdk_window_move() no longer uses XCopyArea all scrolling
now re-renders everything in the window. To get performance
back we use a GtkPixelCache to store already drawn children,
and we when we expose the viewport we just blit the
offscreen to the right place.
This avoids an evil trap when doing MAX (..., ... - 2 * border_width)
and the expression on the right gets promoted to unsigned, instead
of going negative as you would expect.
https://bugzilla.gnome.org/show_bug.cgi?id=699633
