ladybird/Libraries/LibWeb/CSS/FontFace.cpp
Callum Law 668d3afde0 LibWeb: Properly parse attributes for CSS-connected FontFace
Previously we would just set the attributes to the serialized
descriptors, even if they were the empty string.

We now apply defaults when we have empty descriptors and apply parsing
logic from the various `set_*` methods (only applicable to `font-family`
so far where we now extract the value from either a string or a
custom-ident)

Fixes an issue in some css/css-shapes WPT tests where we weren't
properly matching fonts.
2026-01-13 10:40:00 +00:00

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/*
* Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
* Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/ByteBuffer.h>
#include <LibCore/Promise.h>
#include <LibGC/Heap.h>
#include <LibGfx/Font/FontSupport.h>
#include <LibGfx/Font/Typeface.h>
#include <LibGfx/Font/WOFF/Loader.h>
#include <LibGfx/Font/WOFF2/Loader.h>
#include <LibJS/Runtime/ArrayBuffer.h>
#include <LibJS/Runtime/Realm.h>
#include <LibWeb/Bindings/FontFacePrototype.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/CSS/CSSFontFaceRule.h>
#include <LibWeb/CSS/FontComputer.h>
#include <LibWeb/CSS/FontFace.h>
#include <LibWeb/CSS/Parser/Parser.h>
#include <LibWeb/CSS/StyleValues/CustomIdentStyleValue.h>
#include <LibWeb/CSS/StyleValues/StringStyleValue.h>
#include <LibWeb/HTML/Scripting/TemporaryExecutionContext.h>
#include <LibWeb/HTML/Window.h>
#include <LibWeb/Platform/EventLoopPlugin.h>
#include <LibWeb/WebIDL/AbstractOperations.h>
#include <LibWeb/WebIDL/Buffers.h>
#include <LibWeb/WebIDL/Promise.h>
namespace Web::CSS {
static NonnullRefPtr<Core::Promise<NonnullRefPtr<Gfx::Typeface const>>> load_vector_font(JS::Realm& realm, ByteBuffer const& data)
{
auto promise = Core::Promise<NonnullRefPtr<Gfx::Typeface const>>::construct();
// FIXME: 'Asynchronously' shouldn't mean 'later on the main thread'.
// Can we defer this to a background thread?
Platform::EventLoopPlugin::the().deferred_invoke(GC::create_function(realm.heap(), [&data, promise] {
// FIXME: This should be de-duplicated with StyleComputer::FontLoader::try_load_font
// We don't have the luxury of knowing the MIME type, so we have to try all formats.
auto ttf = Gfx::Typeface::try_load_from_externally_owned_memory(data);
if (!ttf.is_error()) {
promise->resolve(ttf.release_value());
return;
}
auto woff = WOFF::try_load_from_bytes(data);
if (!woff.is_error()) {
promise->resolve(woff.release_value());
return;
}
auto woff2 = WOFF2::try_load_from_bytes(data);
if (!woff2.is_error()) {
promise->resolve(woff2.release_value());
return;
}
promise->reject(Error::from_string_literal("Automatic format detection failed"));
}));
return promise;
}
GC_DEFINE_ALLOCATOR(FontFace);
// https://drafts.csswg.org/css-font-loading/#font-face-constructor
GC::Ref<FontFace> FontFace::construct_impl(JS::Realm& realm, String family, FontFaceSource source, FontFaceDescriptors const& descriptors)
{
auto& vm = realm.vm();
// 1. Let font face be a fresh FontFace object. Set font faces status attribute to "unloaded",
// Set its internal [[FontStatusPromise]] slot to a fresh pending Promise object.
auto font_face = realm.create<FontFace>(realm, WebIDL::create_promise(realm));
// Parse the family argument, and the members of the descriptors argument,
// according to the grammars of the corresponding descriptors of the CSS @font-face rule.
// If the source argument is a CSSOMString, parse it according to the grammar of the CSS src descriptor of the @font-face rule.
// If any of them fail to parse correctly, reject font faces [[FontStatusPromise]] with a DOMException named "SyntaxError",
// set font faces corresponding attributes to the empty string, and set font faces status attribute to "error".
// Otherwise, set font faces corresponding attributes to the serialization of the parsed values.
Parser::ParsingParams parsing_params { realm };
auto try_parse_descriptor = [&parsing_params, &font_face, &realm](DescriptorID descriptor_id, String const& string) -> String {
auto result = parse_css_descriptor(parsing_params, AtRuleID::FontFace, descriptor_id, string);
if (!result) {
font_face->reject_status_promise(WebIDL::SyntaxError::create(realm, Utf16String::formatted("FontFace constructor: Invalid {}", to_string(descriptor_id))));
return {};
}
if (result->is_custom_ident())
return result->as_custom_ident().custom_ident().to_string();
return result->to_string(SerializationMode::Normal);
};
font_face->m_family = try_parse_descriptor(DescriptorID::FontFamily, family);
font_face->m_style = try_parse_descriptor(DescriptorID::FontStyle, descriptors.style);
font_face->m_weight = try_parse_descriptor(DescriptorID::FontWeight, descriptors.weight);
font_face->m_stretch = try_parse_descriptor(DescriptorID::FontWidth, descriptors.stretch);
font_face->m_unicode_range = try_parse_descriptor(DescriptorID::UnicodeRange, descriptors.unicode_range);
font_face->m_feature_settings = try_parse_descriptor(DescriptorID::FontFeatureSettings, descriptors.feature_settings);
font_face->m_variation_settings = try_parse_descriptor(DescriptorID::FontVariationSettings, descriptors.variation_settings);
font_face->m_display = try_parse_descriptor(DescriptorID::FontDisplay, descriptors.display);
font_face->m_ascent_override = try_parse_descriptor(DescriptorID::AscentOverride, descriptors.ascent_override);
font_face->m_descent_override = try_parse_descriptor(DescriptorID::DescentOverride, descriptors.descent_override);
font_face->m_line_gap_override = try_parse_descriptor(DescriptorID::LineGapOverride, descriptors.line_gap_override);
RefPtr<StyleValue const> parsed_source;
if (auto* source_string = source.get_pointer<String>()) {
parsed_source = parse_css_descriptor(parsing_params, AtRuleID::FontFace, DescriptorID::Src, *source_string);
if (!parsed_source) {
font_face->reject_status_promise(WebIDL::SyntaxError::create(realm, Utf16String::formatted("FontFace constructor: Invalid {}", to_string(DescriptorID::Src))));
}
}
// Return font face. If font faces status is "error", terminate this algorithm;
// otherwise, complete the rest of these steps asynchronously.
// FIXME: Do the rest of this asynchronously.
if (font_face->status() == Bindings::FontFaceLoadStatus::Error)
return font_face;
// 2. If the source argument was a CSSOMString, set font faces internal [[Urls]] slot to the string.
// If the source argument was a BinaryData, set font faces internal [[Data]] slot to the passed argument.
if (source.has<String>()) {
font_face->m_urls = ParsedFontFace::sources_from_style_value(*parsed_source);
} else {
auto buffer_source = source.get<GC::Root<WebIDL::BufferSource>>();
auto maybe_buffer = WebIDL::get_buffer_source_copy(buffer_source->raw_object());
if (maybe_buffer.is_error()) {
VERIFY(maybe_buffer.error().code() == ENOMEM);
auto throw_completion = vm.throw_completion<JS::InternalError>(vm.error_message(JS::VM::ErrorMessage::OutOfMemory));
font_face->reject_status_promise(throw_completion.value());
} else {
font_face->m_binary_data = maybe_buffer.release_value();
}
}
if (font_face->m_binary_data.is_empty() && font_face->m_urls.is_empty())
font_face->reject_status_promise(WebIDL::SyntaxError::create(realm, "FontFace constructor: Invalid font source"_utf16));
// 3. If font faces [[Data]] slot is not null, queue a task to run the following steps synchronously:
if (font_face->m_binary_data.is_empty())
return font_face;
HTML::queue_global_task(HTML::Task::Source::FontLoading, HTML::relevant_global_object(*font_face), GC::create_function(vm.heap(), [&realm, font_face] {
// 1. Set font faces status attribute to "loading".
font_face->m_status = Bindings::FontFaceLoadStatus::Loading;
// 2. FIXME: For each FontFaceSet font face is in:
// 3. Asynchronously, attempt to parse the data in it as a font.
// When this is completed, successfully or not, queue a task to run the following steps synchronously:
font_face->m_font_load_promise = load_vector_font(realm, font_face->m_binary_data);
font_face->m_font_load_promise->when_resolved([font = GC::make_root(font_face)](auto const& vector_font) -> ErrorOr<void> {
HTML::queue_global_task(HTML::Task::Source::FontLoading, HTML::relevant_global_object(*font), GC::create_function(font->heap(), [font = GC::Ref(*font), vector_font] {
HTML::TemporaryExecutionContext context(font->realm(), HTML::TemporaryExecutionContext::CallbacksEnabled::Yes);
// 1. If the load was successful, font face now represents the parsed font;
// fulfill font faces [[FontStatusPromise]] with font face, and set its status attribute to "loaded".
// FIXME: Are we supposed to set the properties of the FontFace based on the loaded vector font?
font->m_parsed_font = vector_font;
font->m_status = Bindings::FontFaceLoadStatus::Loaded;
WebIDL::resolve_promise(font->realm(), font->m_font_status_promise, font);
// FIXME: For each FontFaceSet font face is in:
font->m_font_load_promise = nullptr;
}));
return {};
});
font_face->m_font_load_promise->when_rejected([font = GC::make_root(font_face)](auto const& error) {
HTML::queue_global_task(HTML::Task::Source::FontLoading, HTML::relevant_global_object(*font), GC::create_function(font->heap(), [font = GC::Ref(*font), error = Error::copy(error)] {
HTML::TemporaryExecutionContext context(font->realm(), HTML::TemporaryExecutionContext::CallbacksEnabled::Yes);
// 2. Otherwise, reject font faces [[FontStatusPromise]] with a DOMException named "SyntaxError"
// and set font faces status attribute to "error".
font->reject_status_promise(WebIDL::SyntaxError::create(font->realm(), Utf16String::formatted("Failed to load font: {}", error)));
// FIXME: For each FontFaceSet font face is in:
font->m_font_load_promise = nullptr;
}));
});
}));
return font_face;
}
// https://drafts.csswg.org/css-font-loading/#font-face-css-connection
GC::Ref<FontFace> FontFace::create_css_connected(JS::Realm& realm, CSSFontFaceRule& rule)
{
HTML::TemporaryExecutionContext execution_context { realm };
auto font_face = realm.create<FontFace>(realm, WebIDL::create_promise(realm));
font_face->m_css_font_face_rule = &rule;
font_face->reparse_connected_css_font_face_rule_descriptors();
if (auto src_value = rule.descriptors()->descriptor(DescriptorID::Src))
font_face->m_urls = ParsedFontFace::sources_from_style_value(*src_value);
rule.set_css_connected_font_face(font_face);
return font_face;
}
void FontFace::reparse_connected_css_font_face_rule_descriptors()
{
auto const& descriptors = m_css_font_face_rule->descriptors();
set_family_impl(*descriptors->descriptor(DescriptorID::FontFamily));
set_style_impl(*descriptors->descriptor_or_initial_value(DescriptorID::FontStyle));
set_weight_impl(*descriptors->descriptor_or_initial_value(DescriptorID::FontWeight));
set_stretch_impl(*descriptors->descriptor_or_initial_value(DescriptorID::FontWidth));
set_unicode_range_impl(*descriptors->descriptor_or_initial_value(DescriptorID::UnicodeRange));
set_feature_settings_impl(*descriptors->descriptor_or_initial_value(DescriptorID::FontFeatureSettings));
set_variation_settings_impl(*descriptors->descriptor_or_initial_value(DescriptorID::FontVariationSettings));
set_display_impl(*descriptors->descriptor_or_initial_value(DescriptorID::FontDisplay));
set_ascent_override_impl(*descriptors->descriptor_or_initial_value(DescriptorID::AscentOverride));
set_descent_override_impl(*descriptors->descriptor_or_initial_value(DescriptorID::DescentOverride));
set_line_gap_override_impl(*descriptors->descriptor_or_initial_value(DescriptorID::LineGapOverride));
}
FontFace::FontFace(JS::Realm& realm, GC::Ref<WebIDL::Promise> font_status_promise)
: Bindings::PlatformObject(realm)
, m_font_status_promise(font_status_promise)
{
}
FontFace::~FontFace() = default;
void FontFace::initialize(JS::Realm& realm)
{
WEB_SET_PROTOTYPE_FOR_INTERFACE(FontFace);
Base::initialize(realm);
}
void FontFace::visit_edges(JS::Cell::Visitor& visitor)
{
Base::visit_edges(visitor);
visitor.visit(m_font_status_promise);
visitor.visit(m_css_font_face_rule);
}
GC::Ref<WebIDL::Promise> FontFace::loaded() const
{
return m_font_status_promise;
}
void FontFace::reject_status_promise(JS::Value reason)
{
if (m_status != Bindings::FontFaceLoadStatus::Error) {
WebIDL::reject_promise(realm(), m_font_status_promise, reason);
WebIDL::mark_promise_as_handled(m_font_status_promise);
m_status = Bindings::FontFaceLoadStatus::Error;
}
}
void FontFace::disconnect_from_css_rule()
{
m_css_font_face_rule = nullptr;
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-family
WebIDL::ExceptionOr<void> FontFace::set_family(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontFamily, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.family setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_family(string));
set_family_impl(property.release_nonnull());
return {};
}
void FontFace::set_family_impl(NonnullRefPtr<StyleValue const> const& value)
{
if (value->is_custom_ident())
m_family = value->as_custom_ident().custom_ident().to_string();
else if (value->is_string())
m_family = value->as_string().string_value().to_string();
else
VERIFY_NOT_REACHED();
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-style
WebIDL::ExceptionOr<void> FontFace::set_style(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontStyle, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.style setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_style(string));
set_style_impl(property.release_nonnull());
return {};
}
void FontFace::set_style_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_style = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-weight
WebIDL::ExceptionOr<void> FontFace::set_weight(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontWeight, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.weight setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_weight(string));
set_weight_impl(property.release_nonnull());
return {};
}
void FontFace::set_weight_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_weight = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-stretch
WebIDL::ExceptionOr<void> FontFace::set_stretch(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
// NOTE: font-stretch is now an alias for font-width
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontWidth, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.stretch setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_width(string));
set_stretch_impl(property.release_nonnull());
return {};
}
void FontFace::set_stretch_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_stretch = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-unicoderange
WebIDL::ExceptionOr<void> FontFace::set_unicode_range(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::UnicodeRange, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.unicodeRange setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_unicode_range(string));
set_unicode_range_impl(property.release_nonnull());
return {};
}
void FontFace::set_unicode_range_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_unicode_range = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-featuresettings
WebIDL::ExceptionOr<void> FontFace::set_feature_settings(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontFeatureSettings, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.featureSettings setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_feature_settings(string));
set_feature_settings_impl(property.release_nonnull());
return {};
}
void FontFace::set_feature_settings_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_feature_settings = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-variationsettings
WebIDL::ExceptionOr<void> FontFace::set_variation_settings(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontVariationSettings, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.variationSettings setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_variation_settings(string));
set_variation_settings_impl(property.release_nonnull());
return {};
}
void FontFace::set_variation_settings_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_variation_settings = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-display
WebIDL::ExceptionOr<void> FontFace::set_display(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::FontDisplay, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.display setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_font_display(string));
set_display_impl(property.release_nonnull());
return {};
}
void FontFace::set_display_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_display = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-ascentoverride
WebIDL::ExceptionOr<void> FontFace::set_ascent_override(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::AscentOverride, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.ascentOverride setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_ascent_override(string));
set_ascent_override_impl(property.release_nonnull());
return {};
}
void FontFace::set_ascent_override_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_ascent_override = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-descentoverride
WebIDL::ExceptionOr<void> FontFace::set_descent_override(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::DescentOverride, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.descentOverride setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_descent_override(string));
set_descent_override_impl(property.release_nonnull());
return {};
}
void FontFace::set_descent_override_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_descent_override = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-linegapoverride
WebIDL::ExceptionOr<void> FontFace::set_line_gap_override(String const& string)
{
// On setting, parse the string according to the grammar for the corresponding @font-face descriptor.
// If it does not match the grammar, throw a SyntaxError; otherwise, set the attribute to the serialization of the
// parsed value.
auto property = parse_css_descriptor(Parser::ParsingParams(), AtRuleID::FontFace, DescriptorID::LineGapOverride, string);
if (!property)
return WebIDL::SyntaxError::create(realm(), "FontFace.lineGapOverride setter: Invalid descriptor value"_utf16);
if (m_css_font_face_rule)
TRY(m_css_font_face_rule->descriptors()->set_line_gap_override(string));
set_line_gap_override_impl(property.release_nonnull());
return {};
}
void FontFace::set_line_gap_override_impl(NonnullRefPtr<StyleValue const> const& value)
{
m_line_gap_override = value->to_string(SerializationMode::Normal);
}
// https://drafts.csswg.org/css-font-loading/#dom-fontface-load
GC::Ref<WebIDL::Promise> FontFace::load()
{
// 1. Let font face be the FontFace object on which this method was called.
auto& font_face = *this;
// 2. If font faces [[Urls]] slot is null, or its status attribute is anything other than "unloaded",
// return font faces [[FontStatusPromise]] and abort these steps.
if (font_face.m_urls.is_empty() || font_face.m_status != Bindings::FontFaceLoadStatus::Unloaded)
return font_face.loaded();
// 3. Otherwise, set font faces status attribute to "loading", return font faces [[FontStatusPromise]],
// and continue executing the rest of this algorithm asynchronously.
m_status = Bindings::FontFaceLoadStatus::Loading;
Web::Platform::EventLoopPlugin::the().deferred_invoke(GC::create_function(heap(), [this] {
// 4. Using the value of font faces [[Urls]] slot, attempt to load a font as defined in [CSS-FONTS-3],
// as if it was the value of a @font-face rules src descriptor.
// 5. When the load operation completes, successfully or not, queue a task to run the follsowing steps synchronously:
auto on_load = GC::create_function(heap(), [this](RefPtr<Gfx::Typeface const> maybe_typeface) {
HTML::queue_global_task(HTML::Task::Source::FontLoading, HTML::relevant_global_object(*this), GC::create_function(heap(), [this, maybe_typeface] {
HTML::TemporaryExecutionContext context(realm(), HTML::TemporaryExecutionContext::CallbacksEnabled::Yes);
// 1. If the attempt to load fails, reject font faces [[FontStatusPromise]] with a DOMException whose name
// is "NetworkError" and set font faces status attribute to "error".
if (!maybe_typeface) {
m_status = Bindings::FontFaceLoadStatus::Error;
WebIDL::reject_promise(realm(), m_font_status_promise, WebIDL::NetworkError::create(realm(), "Failed to load font"_utf16));
// FIXME: For each FontFaceSet font face is in:
}
// 2. Otherwise, font face now represents the loaded font; fulfill font faces [[FontStatusPromise]] with font face
// and set font faces status attribute to "loaded".
else {
m_parsed_font = maybe_typeface;
m_status = Bindings::FontFaceLoadStatus::Loaded;
WebIDL::resolve_promise(realm(), m_font_status_promise, this);
// FIXME: For each FontFaceSet font face is in:
}
}));
});
// FIXME: We should probably put the 'font cache' on the WindowOrWorkerGlobalScope instead of tying it to the document's style computer
auto& global = HTML::relevant_global_object(*this);
if (auto* window = as_if<HTML::Window>(global)) {
auto& font_computer = const_cast<FontComputer&>(window->document()->font_computer());
// Use the connected CSSFontFaceRule otherwise create a dummy one so that we load relative to the document's base URL
GC::Ref<CSSRule> font_face_rule = m_css_font_face_rule ? *m_css_font_face_rule : *CSS::CSSFontFaceRule::create(realm(), CSS::CSSFontFaceDescriptors::create(realm(), {}));
// FIXME: The ParsedFontFace is kind of expensive to create. We should be using a shared sub-object for the data
ParsedFontFace parsed_font_face {
font_face_rule,
m_family,
m_weight.to_number<int>(),
0, // FIXME: slope
Gfx::FontWidth::Normal, // FIXME: width
m_urls,
m_unicode_ranges,
{}, // FIXME: ascent_override
{}, // FIXME: descent_override
{}, // FIXME: line_gap_override
FontDisplay::Auto, // FIXME: font_display
{}, // font-named-instance doesn't exist in FontFace
{}, // font-language-override doesn't exist in FontFace
{}, // FIXME: feature_settings
{}, // FIXME: variation_settings
};
if (auto loader = font_computer.load_font_face(parsed_font_face, move(on_load)))
loader->start_loading_next_url();
} else {
// FIXME: Don't know how to load fonts in workers! They don't have a StyleComputer
dbgln("FIXME: Worker font loading not implemented");
}
}));
// User agents can initiate font loads on their own, whenever they determine that a given font face is necessary
// to render something on the page. When this happens, they must act as if they had called the corresponding
// FontFaces load() method described here.
return font_face.loaded();
}
bool font_format_is_supported(FlyString const& name)
{
// https://drafts.csswg.org/css-fonts-4/#font-format-definitions
if (name.equals_ignoring_ascii_case("collection"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::TrueTypeCollection);
if (name.equals_ignoring_ascii_case("embedded-opentype"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::EmbeddedOpenType);
if (name.equals_ignoring_ascii_case("opentype"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::OpenType);
if (name.equals_ignoring_ascii_case("svg"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::SVG);
if (name.equals_ignoring_ascii_case("truetype"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::TrueType);
if (name.equals_ignoring_ascii_case("woff"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::WOFF);
if (name.equals_ignoring_ascii_case("woff2"sv))
return Gfx::font_format_is_supported(Gfx::FontFormat::WOFF2);
return false;
}
bool font_tech_is_supported(FontTech font_tech)
{
// https://drafts.csswg.org/css-fonts-4/#font-tech-definitions
switch (font_tech) {
case FontTech::FeaturesOpentype:
return Gfx::font_tech_is_supported(Gfx::FontTech::FeaturesOpentype);
case FontTech::FeaturesAat:
return Gfx::font_tech_is_supported(Gfx::FontTech::FeaturesAat);
case FontTech::FeaturesGraphite:
return Gfx::font_tech_is_supported(Gfx::FontTech::FeaturesGraphite);
case FontTech::Variations:
return Gfx::font_tech_is_supported(Gfx::FontTech::Variations);
case FontTech::ColorColrv0:
return Gfx::font_tech_is_supported(Gfx::FontTech::ColorColrv0);
case FontTech::ColorColrv1:
return Gfx::font_tech_is_supported(Gfx::FontTech::ColorColrv1);
case FontTech::ColorSvg:
return Gfx::font_tech_is_supported(Gfx::FontTech::ColorSvg);
case FontTech::ColorSbix:
return Gfx::font_tech_is_supported(Gfx::FontTech::ColorSbix);
case FontTech::ColorCbdt:
return Gfx::font_tech_is_supported(Gfx::FontTech::ColorCbdt);
case FontTech::Palettes:
return Gfx::font_tech_is_supported(Gfx::FontTech::Palettes);
case FontTech::Incremental:
return Gfx::font_tech_is_supported(Gfx::FontTech::Incremental);
// https://drafts.csswg.org/css-fonts-5/#font-tech-definitions
case FontTech::Avar2:
return Gfx::font_tech_is_supported(Gfx::FontTech::Avar2);
}
return false;
}
bool font_tech_is_supported(FlyString const& name)
{
if (auto keyword = keyword_from_string(name); keyword.has_value()) {
if (auto font_tech = keyword_to_font_tech(*keyword); font_tech.has_value()) {
return font_tech_is_supported(*font_tech);
}
}
return false;
}
}