fergalmoran/ladybird
1
0
Fork 0
mirror of https://github.com/fergalmoran/ladybird.git synced 2025-12-22 09:19:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

LibWeb/CSS: Implement legacy name aliases for properties

Browse Source 
When a property is a "legacy name alias", any time it is used in CSS or
via the CSSOM its aliased name is used instead.
(See https://drafts.csswg.org/css-cascade-5/#legacy-name-alias)

This means we only care about the alias when parsing a string as a
PropertyID - and we can just return the PropertyID it is an alias for.
No need for a distinct PropertyID for it, and no need for LibWeb to
care about it at all.

Previously, we had a bunch of these properties, which misused our code
for "logical aliases", some of which I've discovered were not even
fully implemented. But with this change, all that code can go away, and
making a legacy alias is just a case of putting it in the JSON. This
also shrinks `StyleProperties` as it doesn't need to contain data for
these aliases, and removes a whole load of `-webkit-*` spam from the
style inspector.
This commit is contained in:
Sam Atkins
2024-09-27 12:54:08 +01:00
committed by Sam Atkins
parent 2b13079b35
commit fdcece2e88
6 changed files with 113 additions and 243 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
Documentation/Browser/CSSGeneratedFiles.md
View File

@@ -17,6 +17,8 @@ Most of this data is found in the information box for that property in the relev
The file is organized as a single JSON object, with keys being property names, and the values being the data for that property.
Each property will have some set of these fields on it:
(Note that required fields are not required on properties with `legacy-alias-for` or `logical-alias-for` set.)
| Field | Required | Default | Description | Generated functions |
|----------------------------|----------|---------|-------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------|
| `affects-layout` | No | `true` | Boolean. Whether changing this property will invalidate the element's layout. | `bool property_affects_layout(PropertyID)` |
@@ -24,7 +26,8 @@ Each property will have some set of these fields on it:
| `animation-type` | Yes | | String. How the property should be animated. Defined by the spec. See below. | `AnimationType animation_type_from_longhand_property(PropertyID)` |
| `inherited` | Yes | | Boolean. Whether the property is inherited by its child elements. | `bool is_inherited_property(PropertyID)` |
| `initial` | Yes | | String. The property's initial value if it is not specified. | `NonnullRefPtr<CSSStyleValue> property_initial_value(JS::Realm&, PropertyID)` |
| `logical-alias-for` | No | Nothing | String. The name of a property this is an alias for. | |
| `legacy-alias-for` | No | Nothing | String. The name of a property this is an alias for. See below. | |
| `logical-alias-for` | No | Nothing | Array of strings. The name of a property this is an alias for. See below. | |
| `longhands` | No | `[]` | Array of strings. If this is a shorthand, these are the property names that it expands out into. | `Vector<PropertyID> longhands_for_shorthand(PropertyID)` |
| `max-values` | No | `1` | Integer. How many values can be parsed for this property. eg, `margin` can have up to 4 values. | `size_t property_maximum_value_count(PropertyID)` |
| `percentages-resolve-to` | No | Nothing | String. What type percentages get resolved to. eg, for `width` percentages are resolved to `length` values. | `Optional<ValueType> property_resolves_percentages_relative_to(PropertyID)` |
@@ -44,6 +47,16 @@ The [Web Animations spec](https://www.w3.org/TR/web-animations/#animation-type)
| repeatable list | `repeatable-list` |
| (See prose) | `custom` |
### `legacy-alias-for` and `logical-alias-for`
These are two separate concepts, with unfortunately similar names:
- [Legacy name aliases](https://drafts.csswg.org/css-cascade-5/#legacy-name-alias) are properties whose spec names have changed,
but the syntax has not, so setting the old one is defined as setting the new one directly.
For example, `font-stretch` was renamed to `font-width`, so `font-stretch` is now a legacy name alias for `font-width`.
- Logical aliases are properties like `margin-block-start`, which may assign a value to one of several other properties
(`margin-top`, `margin-bottom`, `margin-left`, or `margin-right`) depending on the element they are applied to.
List all the properties that they can alias.
### `quirks`
The [Quirks spec](https://quirks.spec.whatwg.org/#css) defines these.