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LibWeb/CSS: Parse and propagate font-feature-settings property

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Sam Atkins 2024-10-01 09:37:43 +01:00 • committed by Sam Atkins
commit 95c17dfab5
Notes: github-actions[bot] 2024-10-02 15:37:38 +00:00
9 changed files with 129 additions and 1 deletions
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77
Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
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@ -5480,6 +5480,79 @@ RefPtr<CSSStyleValue> Parser::parse_font_language_override_value(TokenStream<Com
return nullptr;
}
RefPtr<CSSStyleValue> Parser::parse_font_feature_settings_value(TokenStream<ComponentValue>& tokens)
{
// https://drafts.csswg.org/css-fonts/#propdef-font-feature-settings
// normal | <feature-tag-value>#
// normal
if (auto normal = parse_all_as_single_keyword_value(tokens, Keyword::Normal))
return normal;
// <feature-tag-value>#
auto transaction = tokens.begin_transaction();
auto tag_values = parse_a_comma_separated_list_of_component_values(tokens);
// "The computed value of font-feature-settings is a map, so any duplicates in the specified value must not be preserved.
// If the same feature tag appears more than once, the value associated with the last appearance supersedes any previous
// value for that axis."
// So, we deduplicate them here using a HashSet.
OrderedHashMap<FlyString, NonnullRefPtr<OpenTypeTaggedStyleValue>> feature_tags_map;
for (auto const& values : tag_values) {
// <feature-tag-value> = <opentype-tag> [ <integer [0,∞]> | on | off ]?
TokenStream tag_tokens { values };
tag_tokens.skip_whitespace();
auto opentype_tag = parse_opentype_tag_value(tag_tokens);
tag_tokens.skip_whitespace();
RefPtr<CSSStyleValue> value;
if (tag_tokens.has_next_token()) {
if (auto integer = parse_integer_value(tag_tokens)) {
if (integer->is_integer() && integer->as_integer().value() < 0)
return nullptr;
value = integer;
} else {
// A value of on is synonymous with 1 and off is synonymous with 0.
auto keyword = parse_keyword_value(tag_tokens);
if (!keyword)
return nullptr;
switch (keyword->to_keyword()) {
case Keyword::On:
value = IntegerStyleValue::create(1);
break;
case Keyword::Off:
value = IntegerStyleValue::create(0);
break;
default:
return nullptr;
}
}
tag_tokens.skip_whitespace();
} else {
// "If the value is omitted, a value of 1 is assumed."
value = IntegerStyleValue::create(1);
}
if (!opentype_tag || !value || tag_tokens.has_next_token())
return nullptr;
feature_tags_map.set(opentype_tag->string_value(), OpenTypeTaggedStyleValue::create(opentype_tag->string_value(), value.release_nonnull()));
}
// "The computed value contains the de-duplicated feature tags, sorted in ascending order by code unit."
StyleValueVector feature_tags;
feature_tags.ensure_capacity(feature_tags_map.size());
for (auto const& [key, feature_tag] : feature_tags_map)
feature_tags.append(feature_tag);
quick_sort(feature_tags, [](auto& a, auto& b) {
return a->as_open_type_tagged().tag() < b->as_open_type_tagged().tag();
});
transaction.commit();
return StyleValueList::create(move(feature_tags), StyleValueList::Separator::Comma);
}
RefPtr<CSSStyleValue> Parser::parse_font_variation_settings_value(TokenStream<ComponentValue>& tokens)
{
// https://drafts.csswg.org/css-fonts/#propdef-font-variation-settings
@ -7620,6 +7693,10 @@ Parser::ParseErrorOr<NonnullRefPtr<CSSStyleValue>> Parser::parse_css_value(Prope
if (auto parsed_value = parse_font_family_value(tokens); parsed_value && !tokens.has_next_token())
return parsed_value.release_nonnull();
return ParseError::SyntaxError;
case PropertyID::FontFeatureSettings:
if (auto parsed_value = parse_font_feature_settings_value(tokens); parsed_value && !tokens.has_next_token())
return parsed_value.release_nonnull();
return ParseError::SyntaxError;
case PropertyID::FontLanguageOverride:
if (auto parsed_value = parse_font_language_override_value(tokens); parsed_value && !tokens.has_next_token())
return parsed_value.release_nonnull();