Instead of keeping a per-FontGroup cache of the previously used fallback
font, cache this value in the caller of `FontGroup::find_by_codepoint`.
The problem with caching this value in the `FontGroup` is that it can
make one layout different from the next.
Still, it is important to cache the value somewhere so that, for
instance, Chinese character don't have to continuously walk through the
entire fallback list when laying out. The heuristic here is to try to
last used font first if the `Script`s match. At the very least this
should make one layout consistent with the next.
Fixes#35704.
Fixes#35697.
Fixes#35689.
Fixes#35679.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Adds support for min-content, max-content, fit-content and stretch,
for block-level elements that don't establish an independent formatting
context, and for block-level elements when there is no float.
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
This change removes the `effective_writing_mode` concept and tries to
properly implement right-to-left layout support for all non-inline
writing modes. In general, what needs to happen is that rectangles
need to be converted to physical rectangles using the containing block.
A right-to-left rectangle's inline start is on the right physical side
of the containing block. Likewise a positive inline offset in
right-to-left text is a negative physical one.
The implementation here is pretty good for most layout modes, but floats
are still a bit in process. Currently, floats are processed in the
logical layout of the block container, but there still might be issues
with float interaction with mixed RTL and LTR.
While this does move us closer to supporting vertical writing modes,
this is still unsupported.
New failures:
- Vertical writing mode not supported:
- `/css/CSS2/floats/floats-placement-vertical-001b.xht`
- `/css/CSS2/floats/floats-placement-vertical-001c.xht`
- Absolutes inlines should avoid floats (#33323)
- `/css/css-position/position-absolute-dynamic-static-position-floats-004.html`
- No support for grid
- `/css/css-align/self-alignment/self-align-safe-unsafe-grid-003.html`
- `/css/css-position/static-position/inline-level-absolute-in-block-level-context-009.html`
- `/css/css-position/static-position/inline-level-absolute-in-block-level-context-010.html`
- Cannot reproduce these locally on any platform. Very mysterious:
- `/css/css-tables/row-group-margin-border-padding.html`
- `/css/css-tables/row-margin-border-padding.html`
- Exposes bugs we have related to hanging whitespace in preserved
whitespace inlines:
- `/css/css-text/white-space/trailing-space-and-text-alignment-rtl-003.html`
- `/css/css-text/white-space/white-space-pre-wrap-trailing-spaces-023.html`
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Rakhi Sharma <atbrakhi@igalia.com>
This adds supports for right-to-left text assigning bidi levels to all
line items when necessary. This includes support for the `dir` attribute
as well as corresponding CSS properties like `unicode-bidi`. It only
implements right-to-left rendering for inline layout at the moment and
doesn't include support for `dir=auto`. Because of missing features,
this causes quite a few tests to start failing, as references become
incorrect due to right-to-left rendering being active in some cases,
but not others (before it didn't exist at all).
Analysis of most of the new failures:
```
- /css/css-flexbox/gap-001-rtl.html
/css/css-flexbox/gap-004-rtl.html
- Require implementing BiDi in Flexbox, because the start and
end inline margins are opposite the order of items.
- /css/CSS2/bidi-text/direction-applies-to-*.xht
/css/CSS2/bidi-text/direction-applies-to-002.xht
/css/CSS2/bidi-text/direction-applies-to-003.xht
/css/CSS2/bidi-text/direction-applies-to-004.xht
- Broken due to a bug in tables, not allocating the
right amount of width for a column.
- /css/css-lists/inline-list.html
- This fails because we wrongly insert a soft wrap opportunity between the
start of an inline box and its first content.
- /css/css-text/bidi/bidi-lines-001.html
/css/css-text/bidi/bidi-lines-002.html
/css/CSS2/text/bidi-flag-emoji.html
- We do not fully support unicode-bidi: plaintext
- /css/css-text/text-align/text-align-end-010.html
/css/css-text/text-align/text-align-justify-006.html
/css/css-text/text-align/text-align-start-010.html
/html/dom/elements/global-attributes/*
- We do not support dir=auto yet.
- /css/css-text/white-space/tab-bidi-001.html
- Servo doesn't support tab stops
- /css/CSS2/positioning/abspos-block-level-001.html
/css/css-text/word-break/word-break-normal-ar-000.html
- Do not yet support RTL layout in block
- /css/css-text/white-space/pre-wrap-018.html
- Even in RTL contexts, spaces at the end of the line must hang and
not be reordered
- /css/css-text/white-space/trailing-space-and-text-alignment-rtl-002.html
- We are letting spaces hang with white-space: pre, but they shouldn't
hang.
```
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Rakhi Sharma <atbrakhi@igalia.com>
Instead of linebreaking inside each single-font text segment, linebreak
the entire inline formatting context at once. This has several benefits:
1. It allows us to use `icu_segmenter` (already in use from style),
which is written against a newer version of the Unicode spec --
preventing breaking emoji clusters.
2. Opens up the possibility of changing the way that linebreaking and
shaping work -- eventually allowing shaping across inline box
boundaries and line breaking *after* shaping.
Co-authored-by: Rakhi Sharma <atbrakhi@igalia.com>
This change adds support for `white-space-collapse: break-spaces` and
adds initial parsing support for `overflow-wrap` and `word-break`. The
later two properties are not fully supported, only in their interaction
with `break-spaces`. This is a preliminary change preparing to implement
them.
In addition, `break_and_shape` is now forked and added to Layout 2020.
This function is going to change a lot soon and forking is preparation
for this. More code that is only used by Layout 2013 is moved from `gfx`
to that crate.
Co-authored-by: Rakhi Sharma <atbrakhi@igalia.com>
This adds an initial implementation of font fallback, on part with the
one used in legacy layout. There are still issues. For instance, font
matching is done per unicode character rather than based on graphemes or
the shape first approach of Chrome. The idea is that these changes can
be made later.
Most tests were only being run for layout-2013, not for layout-2020.
This wasn't great since layout-2020 is now the default.
So this patch unifies the lists of included tests for both layouts.
For layout-2013 this implies adding css/css-content/, css/css-logical/
and css/css-masking/clip/.
For layout-2020 this implies adding several additional css tests, and
also tests like dom/, js/, html/, etc.
