This way, we can also clip the created node bounds to the current clip
of the GtkSnapshot. This works as long as we don't modify the start and
end points, and happens all the time while rendering.
Clipping a color node is trivial so we do it here directly since that
might later save the entire clip node as well as freeing the fragment
shaders from coloring lots of pixels that will be clipped away.
Color matrix nodes as the child of other color matrix nodes can happen
quite frequently as a result of CSS. To ease the renderer
implementations, collapse chains of color matrix nodes into one.
If the rounded clip node is rectilinear, we can simplify it to a normal
clip node. If not, we really need to use a rounded clip node. In both
cases, we can do the same check we do when collecting normal clips and
avoid the clip node altogether if the child node does not get clipped
anyway.
This saves between 3 and 10 nodes in the widget factory, depending on
what page gets rendered.
Clip nodes have a clip rect and we only need to actually create a clip
node if any child node gets clipped at all. If the clip rect conains the
child node bounds entirely, we don't need a clip node.
I got a lot of "clip in clip" cases, for example a CellClip with a
CellTextClip inside. It is really trivial to merge these when we
pop and makes it easier for all backends, so lets do that.
The Vulkan renderer creates a fallback surface for each shadow
node, even if we end up not rendering anything to it. Avoiding
this is a nice optimization.
An empty container has the same effect as transparency
with the cairo renderer, but creates black with Vulkan.
To avoid this, explicitly use a transparent color node.
This fixes the css blendmode example in gtk4-demo with
the Vulkan renderer.
This is important since _push_state returns a pointer into a GArray
which could be invalidated and point to garbage after the subsequent
push_state call.
Instead of creating one GPtrArray per GtkSnapshotState and saving nodes
in there, create one GPtrArray per snapshot and assign a
start_node_index to every GtkSnapshotState as well as a n_nodes variable
so every state knows which nodes belong to it.
This showed up in profiles in certain scenarios, so export a
_get_n_shadows getter instead and let callers provide a sufficiently
large allocated array of GskShadows, which we can use with
g_alloc/g_newa.
We can't pass the same string to two different snapshot states since
removing one of them will free the passed string, so just create another
one for the second state.
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().
... and use it.
The function is a bit awkward because it requires 2 calls to
gtk_snapshot_pop(), but once you accept that, it's very convenient to
use, as can be seen by the 2 implementations.
We already take ints when setting the translation, so it can't
currently take any other values. Additionally, I was seeing large
costs in int -> double -> int for the rects in
gtk_snapshot_clips_rect(), as all callers really are ints (widget
allocations) and the clip region is int-based.
This change completely cleared a 2% rectangle_init_from_graphene from
the profile and is likely to have nice performance effects elsewhere
too.
This means we allocate the collect data with the state, avoiding
an extra allocation. Also, a union means every state object
is the same size and we could reuse the state objects.
... and make the icon rendering code use it.
This requires moving even more shadow renering code into GSK, but so be
it. At least the "shadows not implemented" warning is now gone!
It is now possible to call push() subfunctions for simple container
nodes with just a single child. So you can for example
gtk_snapshot_push_clip() a clip region that all the nodes that get
appended later will then obey.
gtk_snapshot_pop() will then not return a container node, but a clip
node containing the container node (and similar for the transform
example).
This is implemented internally by providing a "collect function" when
pushing that is called when popping to collects all the accumulated
nodes and combine them into the single node that gets returned.
To simplify things even more, gtk_snapshot_pop_and_append() has been
added, which pops the currently pushed node and appends it to the
parent.
The icon rendering code has been converted to this approach.
Instead of appending a container node and adding the nodes to it as they
come in, we now collect the nodes until gtk_snapshot_pop() is called and
then hand them out in a container node.
The caller of gtk_snapshot_push() is then responsible for doing whatever
he wants with the created node.
Another addigion is the keep_coordinates flag to gtk_snapshot_push()
which allows callers to keep the current offset and clip region or
discard it. Discarding is useful when doing transforms, keeping it is
useful when inserting effect nodes (like the ones I'm about to add).
