Browsers such as Chrome and Firefox apply an arbitrary scale to the
current font size if `normal` is used for `line-height`. Firefox uses
1.2 while Chrome uses 1.15. Let's go with the latter for now, it's
relatively easy to change if we ever want to go back on that decision.
This also requires updating the expectations for a lot of layout tests.
The upside of this is that it's a bit easier to compare our layout
results to other browsers', especially Chrome.
Whenever we introduce a block element in a container that at that point
has only had inline children, we create an anonymous wrapper for all the
inline elements so we can keep the invariant that each container
contains either inline or non-inline children. For some reason, we
ignore all the out-of-flow nodes since they are layed out separately and
it was thought that this shouldn't matter.
However, if we are dealing with inline blocks and floating blocks, the
order of the inline contents _including_ out-of-flow nodes becomes very
important: floating blocks need to take the order of nodes into account
when positioning themselves.
Fix this by simply hoisting the out-of-flow nodes into the anonymous
wrapper as well.
Fixes the order of blocks in #4212. The gap is still not present.
In 15103d172c we applied any remaining vertical float clearance to the
BFC's current Y offset for the next block to layout, because a `<br
style="clear: left">` could introduce clearance that would otherwise be
ignored. However, a `<div>` that floats _and_ clears `right` also
introduces this clearance and it is obvious that this should not push
down any subsequent blocks to layout in the current BFC.
Turns out, we don't need this change anymore. Some other later change
also fixed the underlying issue, and by getting rid of the original fix
we can now render https://en.wikipedia.org/wiki/SerenityOS correctly
again.
Fixes#4418.
When determining the content/margin box rects within their ancestor's
coordinate space, we were returning early if the passed in values
already belonged to the requested ancestor. Unfortunately, we had
already applied the used values' offset to the rect, which is the offset
to the ancestor's ancestor.
This simplifies the logic to always apply the rect offset after checking
if we've reached the ancestor. Fixes determining float intrusions inside
block elements with `margin: auto` set.
Fixes#4083.
If a block with inline children ends with a line break clearing any
floats, we not only need to take the introduced clearance into account
for the next line box, but the containing block needs to set the correct
height as well.
Since the spec calls for using the last line box' bottom as the resolved
height (if treated as auto), we now correctly apply the clearance to the
previous line box' bottom coordinate.
Fixes#4058.
We were accidentally providing it with absolute Y-coordinates, messing
up stacked floating boxes that would otherwise intrude on each other.
Fixes#4160.
Whenever we generate line boxes, we might end up with a residual
vertical float clearance by way of having a `<br>` with `clear: ..` set.
Set the Y offset of the next block level box to place by this vertical
clearance.
Relates to #4058.
We were introducing a line break and applying vertical clearance to the
inline formatting context, but that vertical clearance only applied to
new floating boxes. We should move the current block offset to the
vertical clearance to make sure the next line box starts beyond the
cleared floats.
There was a layout test for `<br>` with `clear: ..` set, but that test
did not actually do anything - removing the `clear` property would
result in the same layout. Replace that test with something that
actually tests float clearing.
Relates to #4058.
Our recent change to get rid of the "move 1px at a time" algorithm in
the float positioning logic introduced the issue that potentially
intersecting float boxes were not evaluated in order anymore. This could
result in float boxes being pushed down further than strictly necessary.
By finding the highest point we can move the floating box to and
repeating the process until we're no longer intersecting any floating
box, we also solve some edge cases like intersecting with very long
floating boxes whose edges lay outside the current box' edges.
This is by no means the most efficient solution, but it is more correct
than what we had until now.
Fixes#4110.
We used to always clear the side data after encountering a box with
`clear: ..`, but this is not the right thing to do if that same box also
has `float: ..` set. For example, with `clear: right` and `float: left`
it might be that the next box still wants to clear the right side, and
since the previous box is floating it did not push the next box down far
enough to justify clearing the side data at that point.
This changes the logic to only clear the float side if the clearing box
itself is not floating. We also no longer clear the opposite side after
placing a floating box; that doesn't seem to be necessary anymore.
Fixes#4102.
When generating line boxes, we place floats simultaneously with the
other items on the same line. The CSS text spec requires us to trim the
whitespace at the end of each line, but we only did so after laying out
all the line boxes.
This changes the way we calculate the current line box width for floats
by subtracting the amount of pixels that the current trailing whitespace
is using.
Fixes#4050.
All abspos boxes are expected to be blockified, so we are certain that
we can ignore non-box elements when collecting abspos nodes for layout.
Fixes a crash caused by an attempt to cast a BreakNode to a Box while
performing abspos layout.
...boxes with non-auto height.
We know for sure that by the time we layout abspos boxes, their
containing block has definite height, so it's possible to resolve
non-auto heights and mark it as definite before doing inner layout.
Big step towards having reasonable performance on
https://demo.immich.app/photos because now we avoid a bunch of work
initiated by mistakenly invoked intersection observer callbacks.
Co-Authored-By: Andreas Kling <andreas@ladybird.org>
Height resolution assumes that when available space is definite, it
matches the size of non-anonymous containing block. With this change, we
correctly maintain this assumption when box is wrapped in anonymous
node.
Fixes https://github.com/LadybirdBrowser/ladybird/issues/3422
When setting `font-family: monospace;` in CSS, we have to interpret
the keyword font sizes (small, medium, large, etc) as slightly smaller
for historical reasons. Normally the medium font size is 16px, but
for monospace it's 13px.
The way this needs to behave is extremely strange:
When encountering `font-family: monospace`, we have to go back and
replay the CSS cascade as if the medium font size had been 13px all
along. Otherwise relative values like 2em/200%/etc could have gotten
lost in the inheritance chain.
We implement this in a fairly naive way by explicitly checking for
`font-family: monospace` (note: it has to be *exactly* like that,
it can't be `font-family: monospace, Courier` or similar.)
When encountered, we simply walk the element ancestors and re-run the
cascade for the font-size property. This is clumsy and inefficient,
but it does work for the common cases.
Other browsers do more elaborate things that we should eventually care
about as well, such as user-configurable font settings, per-language
behavior, etc. For now, this is just something that allows us to handle
more WPT tests where things fall apart due to unexpected font sizes.
To learn more about the wonders of font-size, see this blog post:
https://manishearth.github.io/blog/2017/08/10/font-size-an-unexpectedly-complex-css-property/
By the time we're measuring the height of a BFC root, we've already
collapsed all relevant margins for the root and its descendants.
Given this, we should simply use 0 (relative to the BFC root) as the
lowest block axis coordinate (i.e Y value) for the margin edges.
This fixes a long-standing issue where BFC roots were sometimes not tall
enough to contain their children due to margins.
This was mainly a matter of deferring the wrapping of the button's
children until after its internal layout tree has been constructed.
That way we don't lose any pseudo elements spawned along the way.
Fixes#2397.
Fixes#2399.
When positioning floats against an edge, we are taking all current
relevant floats at that side into account to determine the Y offset at
which to place the new float. However, we were using the margin box
height instead of the absolute bottom position, which disregards the
current float's Y-position within the root, and we were setting the Y
offset to that height, instead of taking the new float's Y position
inside of the root into account.
The new code determines the lowest margin bottom value within the root
of the current floats, and adds the difference between that value and
the new float's Y position to the Y offset.
This improves the quality of our font rendering, especially when
animations are involved. Relevant changes:
* Skia fonts have their subpixel flag set, which means that individual
glyphs are rendered at subpixel offsets causing glyph runs as a
whole to look better.
* Fragment offsets are no longer rounded to whole device pixels, and
instead the floating point offset is kept. This allows us to pass
through the floating point baseline position all the way to the Skia
calls, which already expected that to be a float position.
The `scrollable-contains-table.html` ref test needed different table
headings since they would slightly inflate the column size in the test
file, but not the reference.
InlinePaintable was an ad-hoc paintable type required to support the
fragmentation of inline nodes across multiple lines. It existed because
there was no way to associate multiple paintables with a single layout
node. This resulted in a lot of duplicated code between PaintableBox and
InlinePaintable. For example, most of the CSS properties like
background, border, shadows, etc. and hit-testing are almost identical
for both of them. However, the code had to be duplicated to account for
the fact that InlinePaintable creates a box for each line. And we had
quite many places that operate on paintables with a code like:
```
if (box.is_paintable_box()) {
// do something
} else (box.is_inline_paintable()) {
// do exactly the same as for paintable box but using InlinePaintable
}
```
This change replaces the usage of `InlinePaintable` with
`PaintableWithLines` created for each line, which is now possible
because we support having multiple paintables per layout node. By doing
that, we remove lots of duplicated code and bring our implementation
closer to the spec.
It's possible to resolve box's height without doing inner layout, when
computed value is not auto. Doing that fixes height resolution, when box
with percentage height has containing block with percentage height.
Before:
- resolve used width
- layout box's content
- resolve height
After:
- resolve used width
- resolve height if treated as not auto
- layout box's content
- resolve height if treated as auto
When a block container has `clear` set and some clearance is applied,
that clearance prevents margins from adjoining and therefore resets
the margin state. But when a floating box has `clear` set, that
clearance only goes between floating boxes so should not reset margin
state. BlockFormattingContexts already do that correctly, and this PR
changes InlineFormattingContext to do the same.
Fixes#1462; adds reduced input from that issue as test.
The `calculate_inner_width()` and `calculate_inner_height()` resolve
percentage paddings using the width returned by
`containing_block_width_for()`. However, this function does not account
for grids where the containing block is defined by the grid area to
which an item belongs.
This change fixes the issue by modifying `calculate_inner_width()` and
`calculate_inner_height()` to use the already resolved paddings from the
layout state. Corresponding changes ensure that paddings are resolved
and saved in the state before box-sizing is handled.
As a side effect, this change also improves abspos layout for BFC where
now paddings are resolved using padding box of containing block instead
of content box of containing block.
Append text chunks to either the start or end of the text fragment,
depending on the text direction. The direction is determined by what
script its code points are from.
We now follow the rules from the spec more closely, along with an
unspecified quirk for when the offsetParent is a non-positioned body
element. (Spec bug linked in a comment.)
This fixes a whole bunch of css-flexbox tests on WPT, which already had
correct layout, but the reported metrics from JS API were wrong.
When traversing the layout tree to find an appropriate box child to
derive the baseline from. Only the child's margin and offset was being
applied. Now we sum each offset on the recursive call.
Like 1132c858e9, out-of-flow elements such
as float elements would get inserted into block level `::before` and
`::after` pseudo-element nodes when they should instead be inserted as a
sibling to the pseudo element. This change fixes that.
This fixes a few layout issues on the swedish tax agency website
(skatteverket.se). :^)
Although the flex algorithm as specified does say to determine the cross
size of the flex container, this is not how our layout engine works.
The parent formatting context is responsible for sizing its children,
and since that's already happening, we can simply remove the cross
sizing step from FFC.
When iterating inline level chunks for a piece of text like " hello ",
we will get three separate items from InlineLevelIterator:
- Text " "
- Text "hello"
- Text " "
If the first item also had some leading margin (e.g margin-left: 10px)
we would lose that information when deciding that the whitespace is
collapsible.
This patch fixes the issue by accumulating the amount of leading margin
present in any collapsed whitespace items, and then adding them to the
next non-whitespace item in IFC.
It's a wee bit hackish, but so is the rest of the leading/trailing
margin mechanism.
This makes the header menu on https://www.gimp.org/ look proper. :^)
The paintable tree structure more closely matches the painting order
when fragments are owned by corresponding inline paintables. This
change does not affect the layout tree, as it is more convenient for
layout purposes to have all fragments owned by a block container in
one place.
Additionally, this improves performance significantly on pages with
many fragments, as we no longer have to walk the ancestor chain up
to the closest block container to determine if a fragment belongs
to an inline paintable.
This is a part of refactoring towards making the paintable tree
independent of the layout tree. Now, instead of transferring text
fragments from the layout tree to the paintable tree during the layout
commit phase, we allocate separate PaintableFragments that contain only
the information necessary for painting. Doing this also allows us to
get rid LineBoxes, as they are used only during layout.
This patch makes a few changes to the way we calculate line-height:
- `line-height: normal` is now resolved using metrics from the used
font (specifically, round(A + D + lineGap)).
- `line-height: calc(...)` is now resolved at style compute time.
- `line-height` values are now absolutized at style compute time.
As a consequence of the above, we no longer need to walk the DOM
ancestor chain looking for line-heights during style computation.
Instead, values are inherited, resolved and absolutized locally.
This is not only much faster, but also makes our line-height metrics
match those of other engines like Gecko and Blink.
Out-of-flow boxes (floating and absolutely-positioned elements) were
previously collected and put in the anonymous block wrapper as well, but
this actually made hit testing not able to find them, since they were
breaking expectations about tree structure that hit testing relies on.
After this change, we simply let out-of-flow boxes stay in their
original parent, preserving the author's intended box tree structure.
Sizing already worked correctly, but before this change, we were too
aggressive with inserting line breaks when negative margins would
still an atomic inline to fit on the line.
