While 788d5368a7 took care of better text
marker positioning, this improves graphical marker positioning instead.
By looking at how Firefox and Chrome render markers, it's clear that
there are three parts to positioning a graphical marker:
* The containing space that the marker resides in;
* The marker dimensions;
* The distance between the marker and the start of the list item.
The space that the marker can be contained in, is the area to the left
of the list item with a height of the marker's line-height. The marker
dimensions are relative to the marker's font's pixel size: most of them
are a square at 35% of the font size, but the disclosure markers are
sized at 50% instead. Finally, the marker distance is always gauged at
50% of the font size.
So for example, a list item with `list-style-type: disc` and `font-size:
20px`, has 10px between its start and the right side of the marker, and
the marker's dimensions are 7x7.
The percentages I've chosen closely resemble how Firefox lays out its
list item markers.
This commit is a three-parter that is hard to separate without breaking
marker rendering:
1. Any marker style that results in a string, except for a literal
string (e.g. `list-style-type: "@"`), should get the string ". "
appended. We forgot to do this for the alpha and roman types.
2. Instead of using the "pixel size rounded up" from a font and adding
an arbitrary 1 to that, we now use the exact pixel size for as long
as possible to improve our vertical positioning of markers.
3. Instead of always adding a "default marker width" to the marker
content width, we now only do this if we did not have text metrics
available (i.e. the marker style is not a text type). This greatly
improves horizontal positioning of text markers.
Whenever we end up with a scrollable overflow rect that goes beyond
either of its axes (i.e. the rect has a negative X or Y position
relative to its parent's absolute padding box position), we need to clip
that rect to prevent going into the "unreachable scrollable overflow".
This fixes the horizontal scrolling on https://ladybird.org (gets more
pronounced if you make the window very narrow).
...with inline children. This fixes an issue when we ignore abspos boxes
contained by PaintableWithLines while calculating overflow rect size.
Lots of layout tests are affected, because now PaintableWithLines has
overflow rect.
`Text/input/DOM/Element-set-scroll-left.html` is also affected and now
matches other browsers.
The following tests also expose bugs before this PR:
- Layout/input/ol-render-item-values.html: negative ordinal values
- Layout/input/ol-render-deep-hybrid-list-item-list.html: ordinals
deep into the list owner subtree
