Collect scroll roots during the collect_stacking_context phase instead
of during display list construction. This will be useful in order to
collect containing block scroll roots as well as to give scroll roots
sequential ids in the future. This change also pulls stacking context
children out of the StackingContext struct itself, which should reduce
very slightly the memory used by the finished display list. This also
simplifies the DisplayListBuilder because it no longer has to maintain
a stack of ScrollRootIds and StackingContextIds and can instead just
rely on the program stack.
This avoids storing it in the rowgroup (which doesn't need it) and
ensures that it is done sequentially, which will be important when
rowspan support is added to this function.
Note that this does not reduce parallelism in the common case where
all rows are in the same rowgroup.
This is a step in disassociating scrolling areas from stacking
contexts. Now scroll areas are defined by unique ids, which means that
in the future stacking context will be able to contain more than one.
Implement sequential fallback to float speculation
This shouldn't impact any pages that are already rendering correctly, but it is a very naive implementation of this pass.
---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#13284 and fix#13223
- [X] There are tests for these changes
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Simplify the way that stacking contexts are collected. Instead of
passing the StackingContextId down the tree, pass the parent
StackingContext itself. This will allow future patches to get more
information about the parent stacking context (such as location).
Also remove the return value of collect_stacking_contexts, which was
unused.
WebRender.
This happens asynchronously, just as it does in non-WebRender mode.
This functionality is a prerequisite for doing proper display-list-based
hit testing in WebRender, since it moves the scroll offsets into Servo
(and, specifically, into the script thread, enabling iframe event
forwarding) instead of keeping them private to WebRender.
Requires servo/webrender_traits#55 and servo/webrender#277.
Partially addresses #11108.
This is the first part of #10185. More to follow. I have built this locally with both servo and geckolib without errors; let's see if it succeeds on all platforms as well.
`memmove` was showing up high in the profile when concatenating and
shorting display lists. This change drastically reduces the `memmove`
cost in exchange for some minor additional allocation cost.
Flatten display list structure
Instead of producing a tree of stacking contexts, display list
generation now produces a flat list of display items and a tree of
stacking contexts. This will eventually allow display list construction
to produce and modify WebRender vertex buffers directly, removing the
overhead of display list conversion. This change also moves
layerization of the display list to the paint thread, since it isn't
currently useful for WebRender.
To accomplish this, display list generation now takes three passes of
the flow tree:
1. Calculation of absolute positions.
2. Collection of a tree of stacking contexts.
3. Creation of a list of display items.
After collection of display items, they are sorted based upon the index
of their parent stacking contexts and their position in CSS 2.1
Appendeix E stacking order.
This is a big change, but it actually simplifies display list generation.
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Instead of producing a tree of stacking contexts, display list
generation now produces a flat list of display items and a tree of
stacking contexts. This will eventually allow display list construction
to produce and modify WebRender vertex buffers directly, removing the
overhead of display list conversion. This change also moves
layerization of the display list to the paint thread, since it isn't
currently useful for WebRender.
To accomplish this, display list generation now takes three passes of
the flow tree:
1. Calculation of absolute positions.
2. Collection of a tree of stacking contexts.
3. Creation of a list of display items.
After collection of display items, they are sorted based upon the index
of their parent stacking contexts and their position in CSS 2.1
Appendeix E stacking order.
This is a big change, but it actually simplifies display list generation.
This fixes a bug when recalculating border collapsing for an existing table
now. The bug was caused by using `push_or_mutate` which has no effect if there
is already a value at the specified index.
The fix switches incorrect `push_or_mutate` calls to use `push_or_set`
instead. It also renames `push_or_mutate` to `get_mut_or_push` which I think
is a less-confusing name for this method.
Use the PrintTree utility to improve the readability of flow tree
dumps. Blocks and fragments are now split over two dump levels, because
otherwise they are impenetrable. Also start printing the restyle damage of
fragments.
