The "paintable" state in Layout::Box was actually not safe to access
until after layout had been performed.
As a first step towards making this harder to mess up accidentally,
this patch moves painting information from Layout::Box to a new class:
Painting::Box. Every layout can have a corresponding paint box, and
it holds the final used metrics determined by layout.
The paint box is created and populated by FormattingState::commit().
I've also added DOM::Node::paint_box() as a convenient way to access
the paint box (if available) of a given DOM node.
Going forward, I believe this will allow us to better separate data
that belongs to layout vs painting, and also open up opportunities
for naturally invalidating caches in the paint box (since it's
reconstituted by every layout.)
We'll have to do something more proper to support this scenario
eventually, but for now let's at least not crash just because somebody
put an SVG <path> inside an HTML element.
Nobody makes undefined Lengths now, (although actually removing
Undefined will come in a later commit) so we can remove this parameter,
and `resolved_or_auto()`/`resolved_or_zero()`.
Our previous code roughly did this:
1. Generate a bitmap as large as the shadow would end up.
2. Paint a rectangle onto it.
3. Blur the whole bitmap.
4. Split it up and render each section.
This patch takes advantage of the fact that (aside from corners) each
horizontal or vertical strip of a box-shadow is identical to the
others, to generate and blur a much smaller bitmap - only large enough
for the four corners and 1px of central "side" in each direction. This
greatly reduces the memory footprint, and should also speed things up,
since there is much less to blur.
We also pass whether the shadow goes inside or outside the element. Only
outer shadows are rendered currently, and inner ones may want to be
handled separately from them, as they will never interfere with each
other.
Most of the time, we cannot resolve a `calc()` expression until we go to
use it. Since any `<length-percentage>` can legally be a `calc
()`, let's store it in `LengthPercentage` rather than make every single
user care about this distinction.
This is a bit of a hack to get box content to stop bleeding 1px outside
the border sometimes. We will need to come up with a more general
solution for this problem eventually.
Despite looking like it was still needed, it was only used for passing
to other calls to Length::resolved() recursively. This makes the
various `foo.resolved().resolved()` calls a lot less awkward.
(Though, still quite awkward.)
I think we'd need to separate calculated lengths out to properly tidy
these calls up, but one yak at a time. :^)
This reimplements image tiling instead of using `Painter::blit_tiled()`,
so that we will be able to handle CSS's more complicated repetition
rules. (Like `background-repeat: space`) Otherwise this does the same as
before. :^)
Previously, a `background-repeat` value of `no-repeat` in a direction
would cause the image to be drawn at exactly that size. This was fine if
the image was smaller than the element, but if it was larger, it would
draw outside its bounds. Now, it behaves itself. :^)
There's a subtle difference here. A "block box" in the spec is a
block-level box, while a "block container" is a box whose children are
either all inline-level boxes in an IFC, or all block-level boxes
participating in a BFC.
Notably, an "inline-block" box is a "block container" but not a "block
box" since it is itself inline-level.
The logic here is needed by InlineNode too. Moving it into a
`paint_all_borders()` function makes it available to them both, as well
as anyone else who wants it. :^)
When it is called inside `box.for_each_child`, then it may not be called
for the root element. By missing `SVGSVGBox::before_children_paint`
the svg context is not created
The current implementation is missing the emphasized text of the
following rule in the painting order spec:
7. Otherwise: *first for the element*, then for all its in-flow,
non-positioned, block-level descendants in tree order...
This ensures the foreground is painted for the current element before
descending into its children.
This commit unifies methods and method/param names between the above
classes, as well as adds [[nodiscard]] and ALWAYS_INLINE where
appropriate. It also renamed the various move_by methods to
translate_by, as that more closely matches the transformation
terminology.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
When hit testing a stacked context, skip hit testing children if the
child's z-index is less than the parent's. The children are already
sorted by z-index, but also need to consider the parent.
