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.
Now that WebRender uses an Iframe display item, we do not need the Noop
item for the non-WebRender path. We can simply reuse the Iframe display
item. Also remove the layer_id member from the LayeredItem struct, as
it is unused.
`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.
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.
WebRender is an experimental GPU accelerated rendering backend for Servo.
The WebRender backend can be specified by running Servo with the -w option (otherwise the default rendering backend will be used).
WebRender has many bugs, and missing features - but it is usable to browse most websites - please report any WebRender specific rendering bugs you encounter!
DisplayListSection, StackingLevel, and BackgroundAndBorderLevel all
represent pretty much the same thing, a particular section of the
display list. Instead of maintaining three enums which do the same
thing, just use DisplayListSection everywhere. It's a superset of the
other two and this change will make it easier to flatten the DisplayList
in the future for WebRender.
This patch does a number of things, unfortunately all at once:
* Hoists a large subset of the layout wrapper functionality into the style system.
* Merges TElementAttributes into the newly-created TElement.
* Reorganizes LayoutData by style vs layout, and removes LayoutDataShared.
* Simplifies the API for borrowing style/layout data.
There's still more to do to make the style system usable standalone, but
this is a good start.
