ID selectors need to be serialized as identifiers in the spec, but other
hash-values do not. This was causing hex colors that start with a
number, like `#54a3ff`, to serialize as `#\35 4a3ff`, which is silly
and unnecessary.
Selector serialization is done elsewhere, so this case in Token is
probably also unnecessary, but there might be situations I haven't
thought of where serializing an ID does need to happen while it's still
a Token.
After accounting for left-side floats, we have to subtract the offset of
the IFC's containing block again, to get the real starting X offset
for the current line.
This was done correctly in leftmost_x_offset_at() but incorrectly in
available_space_for_line(), causing IFC to break lines too early in
cases where the containing block had a non-zero X offset from the BFC
root block.
This makes SVG-in-HTML behave quite a bit better by following general
replaced layout rules. It also turns <svg> elements into inline-level
boxes instead of block-level boxes.
This helps make the overall codebase consistent. `class_name()` in
`Kernel` is always `StringView`, but not elsewhere.
Additionally, this results in the `strlen` (which needs to be done
when printing or other operations) always being computed at
compile-time.
`static const` variables can be computed and initialized at run-time
during initialization or the first time a function is called. Change
them to `static constexpr` to ensure they are computed at
compile-time.
This allows some removal of `strlen` because the length of the
`StringView` can be used which is pre-computed at compile-time.
Since there is currently no easy way to handle rotations and skews
with LibGfx this only implements translation and scaling by first
constructing a general 4x4 transformation matrix like outlined in
the css-transforms-1 specification. This is then downgraded to a
Gfx::AffineTransform in order to transform the destination rectangle
used with draw_scaled_bitmap()
While rotation would be nice this already looks pretty good :^)
- background properties
- box-shadow
- cursor
- SVG fill/stroke properties
- image-rendering
- outline properties
- pointer-events
- user-select
This should be basically all of them. I skipped `opacity` and
`transform` since establishing a stacking context feels like a
layout-affecting thing, but I could be very wrong on that!
The previous implementation used relative X offsets for both left and
right-side floats. This made right-side floats super awkward, since we
could only determine their X position once the width of the BFC root was
known, and for BFC roots with automatic width, this was not even working
at all most of the time.
This patch changes the way we deal with floats so that BFC keeps track
of the offset-from-edge for each float. The offset is the distance from
the BFC root edge (left or right, depending on float direction) to the
"innermost" margin edge of the floating box.
Floating box are now laid out in two passes: while going through the
normal flow layout, we put floats in their *static* position (i.e the
position they would have occupied if they weren't floating) and then
update the Y position value to the final one.
The second pass occurs later on, when the BFC root has had its width
assigned by the parent context. Once we know the root width, we can
set the X position value of floating boxes. (Because the X position of
right-side floats is relative to the right edge of the BFC root.)
Using the intrinsic size cache means we only perform the nested layout
to determine intrinsic size *once* per root layout pass.
Furthermore, by using a throwaway FormattingState, details of the nested
layout can't leak into and mutate the outer layout.
Instead of caching them with the current state, we can cache them at the
root of the state tree. Since intrinsic sizes are immutable during the
same layout, this allows layout to take advantage of intrinsic sizes
discovered during nested layout (and avoids a *lot* of duplicate work.)
FormattingStates can have parents, in case we're performing nested
layouts to determine something's intrinsic size. In those cases, it will
soon be useful to find the outermost (root) state.
No need to call the expensive establishes_stacking_context() here, as
we've already built the stacking context tree and can simply test for
the presence of existing stacking contexts.
This is preparation for allowing blocks with their own internal BFC to
flow around floating boxes in the parent BFC.
Note that IFC still has the available_space_for_line() API, which
returns space available within the IFC's own containing block, while the
BFC available_space_for_line() returns space available within its root.
In Selectors level 4, `:nth-child()` and `:nth-last-child()` can both
optionally take a selector-list argument. This selector-list acts as a
filter, so that only elements matching the list are counted. For
example, this means that the following are equivalent:
```css
:nth-child(2n+1 of p) {}
p:nth-of-type(2n+1) {}
```
This fixes the specificity for :not(), :is() and :where(). Also, we now
clamp the specificity numbers instead of letting them overflow, and I
sprinkled in some spec comments for good measure.
`<forgiving-selector-list>` and `<forgiving-relative-selector-list>` are
the same as regular selector-lists, except that an invalid selector
does not make the whole list invalid. The former is used by the `:is()`
pseudo-class.
For example:
```css
/* This entire selector-list is invalid */
.foo, .bar, !?invalid { }
/* This is valid, but the "!?invalid" selector is removed */
:is(.foo, .bar, !?invalid) { }
```
Also as part of this, I've removed the `parse_a_selector(TokenStream)`
and `parse_a_relative_selector(TokenStream)` methods as they don't add
anything useful.
It makes no sense to require passing a global object and doing a stack
space check in some cases where running out of stack is highly unlikely,
we can't recover from errors, and currently ignore the result anyway.
This is most commonly in constructors and when setting things up, rather
than regular function calls.
Right now the only functionality supported is getting/setting via JS
and resetting when browsing cross origin.
The HTML Specification (7.11 Browsing the web) also specifies how the
name should be restored from history entries, but we don't have those
yet.
As noted, this is not 100% to the spec, but effectively the same -
`no-preference` is only allowed to appear in features that evaluate it
as false in a boolean context. This is also the only identifier besides
`none` that evaluates to false. If other identifiers gain this property
in the future, we can make it more robust then.
This adds (or at least stubs-out) the following:
- display-mode
- dynamic-range
- environment-blending
- forced-colors
- horizontal-viewport-segments
- vertical-viewport-segments
- inverted-colors
- nav-controls
- prefers-contrast
- prefers-reduced-data
- prefers-reduced-motion
- prefers-reduced-transparency
- scripting
- video-color-gamut
- video-dynamic-range
The `@media (inverted-colors)` CSS that the spec requires we add to the
UA style sheet does not actually do anything for us yet since we don't
support `filter`, but it seemed sensible to include it now to avoid
forgetting later. :^)
This was causing us to miss layout invalidations. With this fixed, we
can remove the invalidation from Element::recompute_style() along with
the associated FIXME.
Thanks to Idan for spotting this! :^)
By the time we're painting, we've already built the stacking context
tree. So instead of asking if a box establishes a stacking context, we
can ask if its paintable *has* a stacking context.
This was taking up ~6% of the profile when mousing around on the HTML
specification. With this change, it disappears completely. :^)
Instead of invalidating style for the entire document, we now locate the
nearest common ancestor between the old and new innermost hovered node,
and only invalidate that ancestor and its descendants.
This drastically reduces the amount of style update work when mousing
around on GitHub (and any other pages, really.) It's actually really
really snappy now. Very cool! :^)
Use the new CSS::property_affects_layout() helper to figure out if we
actually need to perform a full relayout after recomputing style.
There are three tiers of required invalidation after an element receives
new style: none, repaint only, or full relayout.
This avoids the need to rebuild the layout tree (and perform layout on
it) when trivial properties like "color" etc are changed.
This patch adds CSS::property_affects_layout(PropertyID) which tells us
whether a CSS property would affect layout if it were changed.
This will be used to avoid unnecessary relayout work when something
changes that really only requires us to repaint the page.
To mark a property as not affecting layout, set "affects-layout" to
false in the corresponding Properties.json entry. Note that all
properties affect layout by default.
