ladybird/Libraries/LibWeb/CSS/FontFace.h
Sam Atkins d9f12da712 LibWeb: Implement missing code for FontFace/FontFaceSet loading
As FontFaces are added or removed from a FontFaceSet, and as they load
or fail, the FontFaceSet moves them between a few different lists, and
updates its loading/loaded status. In the spec, this is how the
FontFaceSet.[[ReadyPromise]] gets fulfilled: When the document has
finished loading and FontFaceSet.[[LoadingFonts]] is empty, it resolves
the promise.

To support this, FontFace now keeps a set of FontFaceSets that it is
contained in.

This lets us remove the non-spec resolve_ready_promise() call in
EventLoop which was sometimes triggering before any fonts had attempted
to load.

As noted, there's a spec issue with the ready promise: If nothing
modifies the document's fonts, then it would never resolve. My ad-hoc
fix is to also switch the FontFaceSet to the loaded state if it is
empty, which appears to solve the issues but is not ideal.
2026-02-24 15:44:32 +00:00

141 lines
5.3 KiB
C++

/*
* Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibGfx/Font/Typeface.h>
#include <LibURL/URL.h>
#include <LibWeb/Bindings/FontFacePrototype.h>
#include <LibWeb/Bindings/PlatformObject.h>
#include <LibWeb/CSS/ParsedFontFace.h>
namespace Web::CSS {
struct FontFaceDescriptors {
String style = "normal"_string;
String weight = "normal"_string;
String stretch = "normal"_string;
String unicode_range = "U+0-10FFFF"_string;
String feature_settings = "normal"_string;
String variation_settings = "normal"_string;
String display = "auto"_string;
String ascent_override = "normal"_string;
String descent_override = "normal"_string;
String line_gap_override = "normal"_string;
};
class FontFace final : public Bindings::PlatformObject {
WEB_PLATFORM_OBJECT(FontFace, Bindings::PlatformObject);
GC_DECLARE_ALLOCATOR(FontFace);
public:
using FontFaceSource = Variant<String, GC::Root<WebIDL::BufferSource>>;
[[nodiscard]] static GC::Ref<FontFace> construct_impl(JS::Realm&, String family, FontFaceSource source, FontFaceDescriptors const& descriptors);
[[nodiscard]] static GC::Ref<FontFace> create_css_connected(JS::Realm&, CSSFontFaceRule&);
virtual ~FontFace() override;
String family() const { return m_family; }
WebIDL::ExceptionOr<void> set_family(String const&);
void set_family_impl(NonnullRefPtr<StyleValue const> const& value);
String style() const { return m_style; }
WebIDL::ExceptionOr<void> set_style(String const&);
void set_style_impl(NonnullRefPtr<StyleValue const> const& value);
String weight() const { return m_weight; }
WebIDL::ExceptionOr<void> set_weight(String const&);
void set_weight_impl(NonnullRefPtr<StyleValue const> const& value);
String stretch() const { return m_stretch; }
WebIDL::ExceptionOr<void> set_stretch(String const&);
void set_stretch_impl(NonnullRefPtr<StyleValue const> const& value);
String unicode_range() const { return m_unicode_range; }
WebIDL::ExceptionOr<void> set_unicode_range(String const&);
void set_unicode_range_impl(NonnullRefPtr<StyleValue const> const& value);
String feature_settings() const { return m_feature_settings; }
WebIDL::ExceptionOr<void> set_feature_settings(String const&);
void set_feature_settings_impl(NonnullRefPtr<StyleValue const> const& value);
String variation_settings() const { return m_variation_settings; }
WebIDL::ExceptionOr<void> set_variation_settings(String const&);
void set_variation_settings_impl(NonnullRefPtr<StyleValue const> const& value);
String display() const { return m_display; }
WebIDL::ExceptionOr<void> set_display(String const&);
void set_display_impl(NonnullRefPtr<StyleValue const> const& value);
String ascent_override() const { return m_ascent_override; }
WebIDL::ExceptionOr<void> set_ascent_override(String const&);
void set_ascent_override_impl(NonnullRefPtr<StyleValue const> const& value);
String descent_override() const { return m_descent_override; }
WebIDL::ExceptionOr<void> set_descent_override(String const&);
void set_descent_override_impl(NonnullRefPtr<StyleValue const> const& value);
String line_gap_override() const { return m_line_gap_override; }
WebIDL::ExceptionOr<void> set_line_gap_override(String const&);
void set_line_gap_override_impl(NonnullRefPtr<StyleValue const> const& value);
bool is_css_connected() const { return m_css_font_face_rule != nullptr; }
void disconnect_from_css_rule();
void reparse_connected_css_font_face_rule_descriptors();
ParsedFontFace parsed_font_face() const;
Bindings::FontFaceLoadStatus status() const { return m_status; }
GC::Ref<WebIDL::Promise> load();
GC::Ref<WebIDL::Promise> loaded() const;
GC::Ref<WebIDL::Promise> font_status_promise() { return m_font_status_promise; }
void add_to_set(FontFaceSet&);
void remove_from_set(FontFaceSet&);
private:
FontFace(JS::Realm&, GC::Ref<WebIDL::Promise> font_status_promise);
virtual void initialize(JS::Realm&) override;
virtual void visit_edges(Visitor&) override;
void reject_status_promise(JS::Value reason);
// FIXME: Should we be storing StyleValues instead?
String m_family;
String m_style;
String m_weight;
String m_stretch;
String m_unicode_range;
Vector<Gfx::UnicodeRange> m_unicode_ranges;
String m_feature_settings;
String m_variation_settings;
String m_display;
String m_ascent_override;
String m_descent_override;
String m_line_gap_override;
// https://drafts.csswg.org/css-font-loading/#dom-fontface-status
Bindings::FontFaceLoadStatus m_status { Bindings::FontFaceLoadStatus::Unloaded };
GC::Ref<WebIDL::Promise> m_font_status_promise; // [[FontStatusPromise]]
Vector<ParsedFontFace::Source> m_urls; // [[Urls]]
ByteBuffer m_binary_data {}; // [[Data]]
RefPtr<Gfx::Typeface const> m_parsed_font;
RefPtr<Core::Promise<NonnullRefPtr<Gfx::Typeface const>>> m_font_load_promise;
GC::Ptr<CSSFontFaceRule> m_css_font_face_rule;
HashTable<GC::Ref<FontFaceSet>> m_containing_sets;
};
bool font_format_is_supported(FlyString const& name);
bool font_tech_is_supported(FontTech);
bool font_tech_is_supported(FlyString const& name);
}