Follow the computing column measures section of the specification, which
gives an algorithm for setting intrinsic percentage widths when spanning
columns are involved.
Change how we store type of columns. It was used where the specification
only distinguishes between percent and everything else, so it makes more
sense to store and use it as a boolean.
Follow the specification in making the borders centered on the grid
lines. This avoids visual bugs due to double-rendering of borders on
either side of an edge and paves the way for a full implementation of
the harmonization algorithm for collapsed borders.
Currently, this still lacks complete handling of row and column spans.
Also, the box model for cells still considers the full width of the
internal borders instead of just half, as the specification requires.
Some additional handling of rounding issues will be needed to avoid very
subtle visual bugs.
Despite these limitations, this improves the appearance of all the
tables with collapsed borders I've tried while limiting the amount of
change to something reasonable.
This ensures that min-content contributions from cells with no content
are computed using their calculated values, which are never considered
for min-content before then. The specification diverges from column
measures algorithm, which doesn't use specified width of cells anywhere.
The shortcut we put in place didn't resolve percentage widths and
ignored border spacing. We can still return early after we compute the
width per the specifications.
Add logic to compute {min, max}-height and use min-height when
calculating table height, per specifications.
Fixes some issues with phylogenetic tree visualizations on Wikipedia.
Solves conflict in layout tree "type system" when elements <label> (or
<button>) can't have `display: table` because Box can't be
Layout::Label (or Layout::ButtonBox) and Layout::TableBox at the same
time.
This fixes a plethora of rounding problems on many websites.
In the future, we may want to replace this with fixed-point arithmetic
(bug #18566) for performance (and consistency with other engines),
but in the meantime this makes the web look a bit better. :^)
There's a lot more things that could be converted to doubles, which
would reduce the amount of casting necessary in this patch.
We can do that incrementally, however.
This commit implements following missing steps in table layout:
- Calculate final table height
- Resolve percentage height of cells and rows using final table height
- Distribute avilable height to table rows
Instead of special-casing FlexFormattingContext in the intrinsic sizing
layout helpers, add FormattingContext::automatic_content_width() and let
each context subclass decide what that means.
No behavior change here, just moving this responsibility.
Change `compute_auto_height_for_block_level_element` to use max height
(`m_automatic_content_height` produced from TFC) for tables with auto
height which is more correct behaviour than treating them like block
containers.
Introduce `table_box()` function that returns table formatting
context root box casted to `TableBox` similar to how it's done
in other formatting contexts like `root()` in BFC and
`flex_container` in FFC. And replace `context_box()` calls
in TFC with calls to `table_box()`.
Fixup rule that table roots need to be wrapped in anonymous
block boxes need to be implemeted instead of having `TableBox`
inherited from `BlockContainer`.
Change column distribution to take in account is_length() and
is_percentage() width values instead of treating all cells like
they have auto width by implementing it in the way described
in CSS Tables 3 spec:
https://www.w3.org/TR/css-tables-3/#width-distribution-algorithm
distribute_width_to_column() is structured to follow schema:
w3.org/TR/css-tables-3/images/CSS-Tables-Column-Width-Assignment.svg
It is not possible to use width of containing block to resolve
cells width because by the time compute_table_measures() is
called row width is not known yet.
Here I try to address bug where content of table overflows
it's width (hacker news is an example of such site) by
reimplementing some parts of table formatting context.
Now TFC implements first steps of:
https://www.w3.org/TR/css-tables-3/#table-layout-algorithm
but column width and row height distribution steps are
still very incomplete.
This is a big and messy change, and here's the gist:
- AvaliableSpace is now 2x AvailableSize (width and height)
- Layout algorithms are redesigned around the idea of available space
- When doing layout across nested formatting contexts, the parent
context tells the child context how much space is available for the
child's root box in both axes.
- "Available space" replaces "containing block width" in most places.
- The width and height in a box's UsedValues are considered to be
definite after they're assigned to. Marking something as having
definite size is no longer a separate step,
This probably introduces various regressions, but the big win here is
that our layout system now works with available space, just like the
specs are written. Fixing issues will be much easier going forward,
since you don't need to do nearly as much conversion from "spec logic"
to "LibWeb logic" as you previously did.
Instead of formatting contexts flailing around to figure out from the
"inside" how much space is available on the "outside", we should
provide the amount of available space in both axes as an input to run().
This basically means that when something creates a nested formatting
context, the parent context is responsible for telling the nested context
how much space is available for layout. This information is provided
immediately when invoking run().
Note that this commit doesn't pass accurate values in all cases yet.
This first step just makes it build, and passes available values in some
cases where getting them was trivial.
