If a box has a negative margin-left, it may have a negative effective
offset within its parent BFC root coordinate system.
We can account for this when calculating the amount of left-side float
intrusion by flooring the X offset at 0.
This fixes the issue when margin collapsing state was always reset if
a box has clear property not equal to none even if it does not actually
introduce clearance.
This fixes the issue where max margin is used to find offset of
floating box although horizonal margins do not collapse so they need
to be summed instead.
In order to fix this, I also had to reorganize the code so that we
create an independent formatting context even for block-level boxes
that don't have any children. This accidentally improves a table
layout test as well (for empty tables).
While inline content between floating elements was broken correctly,
text justification was still using the original amount of available
space (without accounting for floats) when justifying fragments.
This code now works in terms of *intrusion* by left and right side
floats into a given box whose insides we're trying to layout.
Previously, it worked in terms of space occupied by floats in the root
box of the BFC they participated in. That created a bunch of edge cases
since the code asking about the information wasn't operating in root
coordinate space, but in the coordinate space of some arbitrarily nested
block descendant of the root.
This finally allows horizontal margins in the containing block chain to
affect floats and nested content correctly, and it also allows us to
remove a bogus workaround in InlineFormattingContext.
`Length::resolved(Node&)` transforms infinite values to "auto".
Following transformations:
Infinite (Length) -> "auto" -> 0 (px)
cause border-box width to be resolved in zero when it should be inf px.
Removing `Length::resolved(Node&)` makes it work right:
Infinite (Length) -> Infinite (px)
Fixes#18649
https://www.w3.org/TR/CSS22/visuren.html#floats says that when a box
establishes BFC it should not overlap with floats. The way to avoid
overlaps is up to implementor. This change implements avoiding overlap
by narrowing width of a box because it seems like what other engines
do (in the scenarios I tested).
When there are floats present inside an IFC, we must coordinate with
the parent BFC to calculate the automatic width of the IFC's block box.
This is because the IFC is not directly aware of floats. Only the BFC
knows enough about them to account for them in automatic sizing.
Fixes the problem that width is incorrectly computed in intrinsic
sizing mode when there are blocks that have min-width or max-width
specified.
Actually that is just the fix of a symptom of the larger problem that
Length::to_px() returns 0 when value is auto regardless of available
size.
If there is a remaining margin-bottom in margin collapsing state
tracker after laying out all boxes in the current BFC, it must be
assigned to the last in-flow child since margin collapsing cannot
occur across a formatting context boundary.
The current issue where margin-bottom may be counted twice due to
"collapse through" margins in the last in-flow child box is addressed
with this fix by excluding such boxes during the search for a box to
assign the remaining margin.
Test case coming with this fix has a layout bug with incorrectly
computed line height.
When calculating the intrinsic width of a block-level box, we now ignore
the preferred width entirely, and not just when the preferred width
should be treated as auto.
The condition for this was both confused and wrong, as it looked at the
available width around the box, but didn't check for a width constraint
on the box itself.
Just because the available width has an intrinsic sizing constraint
doesn't mean that the box is undergoing intrinsic sizing. It could also
be the box's containing block!
