Instead annotate all flows with their owning ScrollRoots. When
processing the display list items into a flattened display list, we add
PushScrollRoot and PopScrollRoot to signal when scrolling regions start
and end. It is possible for content from different scrolling regions to
intersect and when they do, the stack of scrolling regions is
duplicated. When these duplicated scrolling regions stacks reach
WebRender, it will scroll them in tandem.
The PushScrollRoot and PopScrollRoot items are currently represented as
StackingContexts in WebRender, but eventually these will be replaced
with special WebRender display items.
Fixes#13529.
Fixed#13298.
This makes the API used to build display lists quite a bit simpler and
reduces the amount of auxiliary data structures that need to be passed
around. It is also important preparation work for separating scrolling
areas from stacking contexts.
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.
Layers were a feature of the legacy drawing path. If we re-add them at
some point, it probably makes more sense to make them a product of
display list inspection.
This change also remove a bunch of dead painting code.
Remove the concept of nested stacking contexts from display list builder
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With the removal of the legacy rendering path, we don't need to worry
about nested stacking contexts. This change just pushes the
complication to the WebRender conversion step, but a later change will
remove the concept from WebRender as well.
This also helps to prepare for the introduction of ids for particular
scrolling regions, an integral part of multiple ScrollLayers per block.
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With the removal of the legacy rendering path, we don't need to worry
about nested stacking contexts. This change just pushes the
complication to the WebRender conversion step, but a later change will
remove the concept from WebRender as well.
This also helps to prepare for the introduction of ids for particular
scrolling regions, an integral part of multiple ScrollLayers per block.
border box positions and transforms into account.
Clipping region computation now follows a simple process: (1) in the
parent's coordinate system, parents store appropriate clipping regions
into children; (2) each child moves its clipping region to its own
coordinate system if necessary.
Because clipping region computation is now based on stacking-relative
border box positions and the `transform_rect` method, it can handle
`position: relative` offsets and more types of transforms, such as
scaling.
Improves etsy.com.
Closes#13753.
Integrate stacking contexts into the display list
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- [ ] These changes fix #__ (github issue number if applicable).
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Integrate stacking contexts into the display list by adding two new
entry types, PushStackingContext and PopStackingContext. This allows us
to eliminate the ugly offsets map that DisplayList used to contain
and seems to speed up display list construction. With this approach
we are able to also completely prune pseudo-stacking contexts from the
final display list and remove their (minimal) overhead from display
list traversal Traversing the display list is also a bit simpler now.
Additionally, this will allow easier editing of the DisplayList to
properly support scrolling roots. The push/pop entries can be
duplicated to clone complex StackingContext trees between layers.
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Integrate stacking contexts into the display list by adding two new
entry types, PushStackingContext and PopStackingContext. This allows us
to eliminate the ugly offsets map that DisplayList used to contain
and seems to speed up display list construction. With this approach
we are able to also completely prune pseudo-stacking contexts from the
final display list and remove their (minimal) overhead from display
list traversal Traversing the display list is also a bit simpler now.
Additionally, this will allow easier editing of the DisplayList to
properly support scrolling roots. The push/pop entries can be
duplicated to clone complex StackingContext trees between layers.
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.
Simplify the situations in which subpixels are accumulated, so that it
is only done for translation or identity transformation matrices. Also,
apply accumulated subpixels to more operations in PaintContext. This
fixes several pre-existing reftests and hopefully will eliminate
off-by-one errors in flaky reftests.
Fixes#10881.
Instead of simply rounding layer origins and discarding subpixel
offsets, accumulate them by transforming them into the space of the
next child stacking context. This is an attempt to eliminate subpixel
differences that are caused by different stacking context boundaries in
reference tests.
Currently these accumulated subpixels are only used for text
positioning, but the plan is that they can be used for all drawing in
the future.
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.
Replace character indices with UTF-8 byte offsets throughout the code dealing
with text shaping and breaking. This eliminates a lot of complexity when
converting from one to the other, and interoperates better with the rest of
the Rust ecosystem.
We don't really need two levels of abstraction for every element in the
DisplayList. This simplifies the complexity of the data structure in
preparation for providing documentation and properly handling scrolling
roots.
This allows WebRender to correctly render complex clipping regions that
can be reduced to single rounded rectangles. WebRender still can't
render rounded rectangles with arbitrary intersections yet, but this
allows it to handle many more cases.
Closesservo/webrender#241.
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.
over the data as well.
WebRender doesn't need the data, as it acquires it separately.
About a 50%-100% improvement in display list building time on
browser.html.
