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.
Painting command executors are defined within the "Painting" namespace,
allowing us to remove this prefix from their names.
This commit performs the following renamings:
- Painting::PaintingCommandExecutor to Painting::CommandExecutor
- Painting::PaintingCommandExecutorCPU to Painting::CommandExecutorCPU
- Painting::PaintingCommandExecutorGPU to Painting::CommandExecutorGPU
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
