This changes textview to share the style context with the pixelcache.
Doing so allows pixel cache to optimize the surface creation and use
a CAIRO_CONTENT_COLOR instead of CAIRO_CONTENT_COLOR_ALPHA when
appropriate.
https://bugzilla.gnome.org/show_bug.cgi?id=754658
We can take a fast path if the background for a widget is opaque by using
a CAIRO_CONTENT_COLOR instead of a CAIRO_CONTENT_COLOR_ALPHA surface. Most
blit'ing backends have a fast path for this, including Pixman and Quartz.
https://bugzilla.gnome.org/show_bug.cgi?id=754658
This new private API, _gtk_style_context_is_background_opaque(), is meant to
be used by internal Gtk+ wigets to optimize fast paths for cases where
applicable. One such use would be to use a CAIRO_CONTENT_COLOR surface
instead of CAIRO_CONTENT_COLOR_ALPHA.
https://bugzilla.gnome.org/show_bug.cgi?id=754658
This avoids a bunch of allocations, and additionally it has better
cache behaviour, as we don't follow pointers to the separate GList
node memory areas during traversal.
From Christian Hergert:
This machine is a Retina mac book pro so I've been working on getting
GtkTextView (GtkPixelCache) up to our performance level on
X11/Wayland. I'm seeing a jump from about 43 FPS to about 50 FPS.
https://bugzilla.gnome.org/show_bug.cgi?id=754687
Merge it into GtkWidgetPrivate. In my measurements, about half
of all widgets have a non-default auxinfo struct, and we use this
information in size allocation, so it is nice to avoid the gdata
overhead.
We only use widget paths for a few widgets nowadays (notebook,
treeview, pathbar, combobox), so we can save some space by
not having this field in GtkWidgetPrivate.
The hash table is only accessed at creation and destruction time,
and many widgets don't use templates at all, so no need to have
this permanently occupying space.
This reverts commit 3eacfa88f2.
Apart from the patch not being correct, we don't want to expose private
structures in header files if we can avoid it.
And this type-checking overhead is not an optimization that is even
measurable.
https://bugzilla.gnome.org/show_bug.cgi?id=754932
Statistics for the gtk3-demo listbox example show that the
vast majority of calls to _gtk_allocated_bitmask_resize go
from a size of 2 to 2. Don't needlessly call realloc() in
this case.
The previous code was crashing when used as the returned classes array
would have been invalid after the first deletion. So if a 2nd class
would be deleted, invalid memory might have been referenced.
