Implement collapsing of a box margin-top and first in-flow
child margin-top by saving function that updates y position
of containing block inside BlockMarginState and then for
every child until "non-collapsed through" child is reached
y position of containing block is updated by calling
update_box_waiting_fox_final_y_position_callback.
Previously y position of boxes in block formatting context
was calculated by looking at y position of previous in-flow
sibling and adding collapsed margin of "collapse through"
boxes lying between box currently being laid out and it's
previous in-flow sibling.
Here introduced BlockMarginState structure that maintains
array of currently collapsible margins hence we no longer
need to look at previous sibling to calculate y position
of a box.
Bug was introduced in 210bf8adf0c431be05659140fd6de3a2cc5b7d99
It makes new variable for independent_formatting_context instead
of using earlier declared one which means that
parent_context_did_dimension_child_root_box will never be called.
This fixes a few sizing issues too. The page size is now correct in most
cases! \o/
We get to remove some of the `to_type<>()` shenanigans, though it
reappears in some other places.
Even if block has all children inline there need to be a check
if it creates BFC because otherwise IFC will be looking in
wrong parent BFC to calculate space used by floats.
We were neglecting to resolve the used horizontal padding and border
properties on block-level boxes when treating their width as `auto`
during intrinsic sizing.
This led to padding and border not contributing to the intrinsic width
of their containing block
Calling parent_context_did_dimension_child_root_box immediately after
laying out the inside of the floating box is not correct, as we haven't
worked out the dimensions of the floating box yet.
In particular, this caused the icons in the top bar of Cookie Clicker
to not hug the top of the viewport. This is because the icons are
absolutely positioned elements inside a floating element which has
padding applied to it. Since we laid out the abspos element before
the floating element, it got padding values of 0 from the parent, the
default value, meaning it didn't take away the padding of it's floating
parent.
This follows how abspos boxes layout their inside boxes as well.
We were incorrectly resolving them against the available width, which
may or may not be the same as the containing block width.
The specification for these properties says that percentages resolve
against the containing block width, so that's what we should do.
After speaking with fantasai at CSSWG about this, it turns out I had
misunderstood intrinsic heights. I originally believed all intrinsic
sizes had to be computed with no influence from the surrounding context.
As it turns out, intrinsic heights *are* influenced by the available
width, since it's needed to determine where lines break.
The APIs for calculating min-content and max-content heights now take
the available width as inputs. This instantly improves layout in many
cases where we'd previously make things way too wide.
When an absolutely positioned box has auto insets on both sides of an
axis, it's placed according to the "static position rectangle". This is,
roughly, the rectangle a box would occupy if it were position:static
instead of position:absolute or position:fixed.
This patch implements a rough, but still significantly better,
estimation of such static positions. It gets pretty hairy in the case
where an abspos box has a parent whose children are inline.
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.
This patch changes the *computed* representation of the following CSS
properties to use CSS::Size:
- width, min-width, max-width
- height, min-height, max-height
A few things had to change in order for things to keep working,
but I tried to keep the diff to a minimum.
The main trouble was that `min-width` and `max-width` can't actually be
`auto`, but they *can* be `none`. We previously treated `auto` as a
valid value (and it behaved mostly like `none`).
This was used by FFC to estimate the height of flex items after
performing layout inside them.
Now that we have automatic_content_height(), we no longer need this
awkward API and we can fold it into BFC's own height calculation.
This function should return the automatic height of the formatting
context's root box.
Until now, we've been relying on some magical handshakes between parent
and child context, when negotiating the height of child context root
boxes. This is a step towards something more reasonable.
We were forgetting to convert to and from BFC root relative coordinates
when calculating how much clearance was needed to get past floats.
This fixes the last remaining issue on Acid1, which is now perfect. :^)
We already had a helper for this, but compute_height() wasn't using it.
Tweak it so that compute_height() can use it, and remove the duplicated
code that's now redundant.
This patch combines a number of techniques to make inline content flow
more correctly around floats:
- During inline layout, BFC now lets LineBuilder decide the Y coordinate
when inserting a new float. LineBuilder has more information about the
currently accumulated line, and can make better breaking decisions.
- When inserting a float on one side, and the top of the newly inserted
float is below the bottommost float on the opposite side, we now reset
the opposite side back to the start of that edge. This improves
breaking behavior between opposite-side floats.
- After inserting a float during inline layout, we now recalculate the
available space on the line, but don't adjust X offsets of already
existing fragments. This is handled by update_last_line() anyway,
so it was pointless busywork.
- When measuring whether a line can fit at a given Y coordinate, we now
consider both the top and bottom Y values of the line. This fixes an
issue where the bottom part of a line would bleed over other content
(since we had only checked that the top Y coordinate of that line
would fit.)
There are some pretty brain-dead algorithms in here that we need to make
smarter, but I didn't want to complicate this any further so I've left
FIXMEs about them instead.
This remained undetected for a long time as HeaderCheck is disabled by
default. This commit makes the following file compile again:
// file: compile_me.cpp
#include <LibWeb/CSS/GridTrackSize.h>
// That's it, this was enough to cause a compilation error.
By asking if the value *contains* a percentage rather than whether it
*is* one, we cover many more cases where e.g `width: calc(100% - 10px)`
should be "treated as auto" etc.
If the containing block has indefinite height, we can't resolve
percentage heights against it. Instead of treating it as 0 by accident,
let's treat it as "auto" on purpose.
This brings back the cheek borders on Acid2.
- Use the border box of the floated element when testing if something
needs to flow around it.
- Take the floated element's containing block size into account (instead
of the BFC root) when calculating available space on a line where a
right-side float intrudes.
Factor out the code that computes the vertical position of a Box with
respect to its siblings so that it can be used when computing the
absolutely positioned divs as well.
This commit moves both the ImageStyleValue and LinearGradientStyleValue
to a common base class of AbstractImageStyleValue. This abstracts
getting the natural_width/height, loading/resolving, and painting
the image.
Now for 'free' you get:
- Linear gradients working with the various background sizing/repeat
properties.
- Linear gradients working as list-markers :^) -- best feature ever!
P.s. This commit is a little large as it's tricky to make this change
incrementally without breaking things.
This state is less static than we originally assumed, and there are
special formatting context-specific rules that say certain sizes are
definite in special circumstances.
To be able to support this, we move the has-definite-size flags from
the layout node to the UsedValues struct instead.
This patch adds a separate entry point for this kind of layout.
We override it in BFC to set up initial width/height values for the
BFC root block.
Resulting dimensions are assigned as content_width and content_height
at the end of intrinsic sizing, for each axis, if it's either "auto"
or there's a min-content or max-content constraint in effect.
