This change is a preparation before introducing Skia painter in an
upcoming change. It's needed because Skia does not have an API to
implement ClearClipRect command. It only allows to return previous
clip rect by popping from its internal state stack.
A bit more context: initially we had save and restore commands, but
their frequent use led to many reallocations of vector during painting
commands recording. To resolve this, we switched to SegmentedVector to
store commands list, which allows fast appends. Now, having many save
and restore commands no longer causes noticeable performance issue.
Before this change we were painting inner shadows lying outside of
viewport.
Improves painting performance on Github and Twitter where this command
is used a lot.
`Painting::paint_all_borders()` only uses `.draw_line()` for simple
borders and `.fill_path()` for more complex cases. These are both
already supported by the `RecordingPainter` so removing this command
simplifies the painting API.
Two test changes:
css-background-clip-text: Borders are now drawn via the AA painter
(which makes them closer to how they appear in other browsers).
corner-clip-inside-scrollable: Borders removed (does not change test)
due to imperceptible sub-pixel changes.
PaintFrame is not primitive painting command, we inherited from OS, that
is hard to replicate in GPU-painter or alternative CPU-painter API. We
should remove it as a part of refactoring towards simplifying recording
painter commands set.
Fixes: #23796
From https://drafts.csswg.org/css-backgrounds-4/#background-clip
"The background is painted within (clipped to) the intersection of the
border box and the geometry of the text in the element and its in-flow
and floated descendants"
This change implements it in the following way:
1. Traverse the descendants of the element, collecting the Gfx::Path of
glyphs into a vector.
2. The vector of collected paths is saved in the background painting
command.
3. The painting commands executor uses the list of glyphs to paint a
mask for background clipping.
Co-authored-by: Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
...to avoid allocating a copy of glyph run for painting commands. We
can't simply save pointers to a glyph run in layout/paintable tree
because it should be safe to deallocate layout and paintable trees
after painting commands are recorded, if in the future we decide to
move command execution to a separate thread.
Instead of allocating a new glyph run to scale glyph positions and
fonts, a scale factor could be encoded in a paint command and applied
later during command execution.
Instead of allocating a new glyph run solely to shift each glyph by the
painter's offset, this offset could be encoded in a paint command and
applied later during command execution.
Separating the recorder list from the painter will allow us to save it
for later execution without carrying along the painter's state. This
will be useful once we have a separate thread for executing painting
commands, to which we will have to transfer commands from the main
thread.
Preparation for https://github.com/SerenityOS/serenity/pull/23108
