Add a GTK_STYLE_CONTEXT_PRINT_SHOW_CHANGE flag that
tells gtk_style_context_to_string to include the
change values of nodes in the output. This will
help debugging css change tracking.
Most of the time when styles need to be recreated, the name and classes
of the css node haven't changed. In this case, the change value will not
change either, since we are computing change under the assumption that
name and classes are unchanged.
So don't recompute the change. This avoids the second match we do to
find the superset, cutting down the number of times we consult the
selector tree.
The idea is that this reduce the amount of frequently
changing state that css nodes are sensitive to.
This is going to reduce the amount of style recomputation.
This is just lots of renaming.
The interface remains private, so the public API does not change, apart
from removing the definition of the Interface object to avoid
subclassing.
~Company ╡ so TL;DR: we put the static style in the cache, but then
⤷ ╡ compute a child style from the animated style in the cache
⤷ ╡ and we put the child style also in the cache (because
⤷ ╡ it's not animated)
⤷ ╡ then we run the animation, but reuse the cache every time
⤷ ╡ for both child and parent
⤷ ╡ so after the animation is done, we end up with a cache that
⤷ ╡ has the correct static style for the parent but an
⤷ ╡ incorrect static style for the child
⤷ ╡ because that static style was computed from the
⤷ ╡ initial animated style
This fixes https://bugzilla.gnome.org/show_bug.cgi?id=763517
Previously this setting would just invalidate the whole CSS tree and
thereby hopefully avoid all cache usage.
Now, we actually don't cause extra invalidations anymore, but instead
avoid ever inserting anything into the cache when this setting is set.
For now, the split out style cache doesn't cache anything. This is
mostly to make sure that bisections of wrong caching behavior will
bisect down to the commit that actually adds caching.
Drop the custom style printing implementation in gtkcssnode.c and
instead reuse the existing gtk_css_style_print function, extending
it a bit to suit our needs.
Instead of computing values, just recognize initial values by
having no CSS section. Also do away with the show-initial flag, and
just always filter out initial values. The flag can come back when
it is needed.
The node declaration has all the information we are printing
here (except for visibility). At the same time, redo the format
to print the information in selector format, and indicate
(in)visibility by enclosing the selector in square brackets.
Add a gtk_style_context_to_string function that can serialize
a CSS node or tree of nodes, optionally including CSS properties
as well.
This will be useful in writing tests.
Invisible nodes don't change the first/last-child status of the nodes
after/before them. That means we don't have to just check the state of
the adjacent node when modifying this state, but all their siblings
until we hit a visible node.
The same way, a node is not the first child if it has no previous
sibling, it is the first child if it has no previous visible sibling.
This is important for caching in the global lookup cache.
gtk_css_node_insert_before/after can easily create cycles
which later lead to stack overflows. Even if we're not
catching all cycles here, at least we can detect obviously
invalid arguments, such as inserting a node next to itself.
When we reuse styles that didn't change across changes to the source
CSS, make sure we clear the caches. Otherwise child nodes will pick up
styles from the old source CSS.
In commit 2c61316677 we avoided emitting
the style-changed signal if no CSS property changed.
Unfortunately, this also caused CSS styles to not be updated when
animations started if those animations did not change any CSS value
immediately. In those cases the animation would just never start.
The obvious example was the spinner.
Catch the case where a CSS style did not change and don't emit the
style-changed signal in that case.
This saves not only the emission of the signal, but also doesn't cause
invalidation in child nodes, which would previously get a PARENT_STYLE
Instead of having old and new style, now have a GtkCssStyleChange opaque
object that will compute the changes you are interested in for you.
This simplifies change signal handlers quite a bit and avoids lots of
repeated computation in every signal handler.
