ladybird/Userland/Libraries/LibWeb/CSS/StyleComputer.h
Andreas Kling 1f9aed2617 LibWeb: Load and use fonts described by @font-face rules :^)
When encountering a @font-face rule, StyleComputer will now fire off
a resource request and download the first source URL specified.

Once downloaded, we try to parse it as a TrueType font file, and if it
works, it's added to a cache in StyleComputer. This effectively makes
fonts per-document since every document has its own StyleComputer.

This is very unoptimized and could definitely use some caching, etc.
But it does work on Acid3. :^)
2022-03-29 02:14:20 +02:00

123 lines
4.2 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <AK/NonnullRefPtrVector.h>
#include <AK/Optional.h>
#include <AK/OwnPtr.h>
#include <LibWeb/CSS/CSSFontFaceRule.h>
#include <LibWeb/CSS/CSSStyleDeclaration.h>
#include <LibWeb/CSS/Parser/StyleComponentValueRule.h>
#include <LibWeb/CSS/Selector.h>
#include <LibWeb/CSS/StyleProperties.h>
#include <LibWeb/Forward.h>
namespace Web::CSS {
struct MatchingRule {
RefPtr<CSSStyleRule> rule;
size_t style_sheet_index { 0 };
size_t rule_index { 0 };
size_t selector_index { 0 };
u32 specificity { 0 };
};
class PropertyDependencyNode : public RefCounted<PropertyDependencyNode> {
public:
static NonnullRefPtr<PropertyDependencyNode> create(String name)
{
return adopt_ref(*new PropertyDependencyNode(move(name)));
}
void add_child(NonnullRefPtr<PropertyDependencyNode>);
bool has_cycles();
private:
explicit PropertyDependencyNode(String name);
String m_name;
NonnullRefPtrVector<PropertyDependencyNode> m_children;
bool m_marked { false };
};
class StyleComputer {
public:
explicit StyleComputer(DOM::Document&);
~StyleComputer();
DOM::Document& document() { return m_document; }
DOM::Document const& document() const { return m_document; }
NonnullRefPtr<StyleProperties> create_document_style() const;
NonnullRefPtr<StyleProperties> compute_style(DOM::Element&, Optional<CSS::Selector::PseudoElement> = {}) const;
// https://www.w3.org/TR/css-cascade/#origin
enum class CascadeOrigin {
Author,
User,
UserAgent,
Animation,
Transition,
};
Vector<MatchingRule> collect_matching_rules(DOM::Element const&, CascadeOrigin, Optional<CSS::Selector::PseudoElement>) const;
void invalidate_rule_cache();
Gfx::Font const& initial_font() const;
void did_load_font(FlyString const& family_name);
private:
void compute_cascaded_values(StyleProperties&, DOM::Element&, Optional<CSS::Selector::PseudoElement>) const;
void compute_font(StyleProperties&, DOM::Element const*, Optional<CSS::Selector::PseudoElement>) const;
void compute_defaulted_values(StyleProperties&, DOM::Element const*, Optional<CSS::Selector::PseudoElement>) const;
void absolutize_values(StyleProperties&, DOM::Element const*, Optional<CSS::Selector::PseudoElement>) const;
void transform_box_type_if_needed(StyleProperties&, DOM::Element const&, Optional<CSS::Selector::PseudoElement>) const;
void compute_defaulted_property_value(StyleProperties&, DOM::Element const*, CSS::PropertyID, Optional<CSS::Selector::PseudoElement>) const;
RefPtr<StyleValue> resolve_unresolved_style_value(DOM::Element&, PropertyID, UnresolvedStyleValue const&) const;
bool expand_unresolved_values(DOM::Element&, StringView property_name, HashMap<FlyString, NonnullRefPtr<PropertyDependencyNode>>& dependencies, Vector<StyleComponentValueRule> const& source, Vector<StyleComponentValueRule>& dest, size_t source_start_index) const;
template<typename Callback>
void for_each_stylesheet(CascadeOrigin, Callback) const;
Gfx::IntRect viewport_rect() const;
float root_element_font_size() const;
struct MatchingRuleSet {
Vector<MatchingRule> user_agent_rules;
Vector<MatchingRule> author_rules;
};
void cascade_declarations(StyleProperties&, DOM::Element&, Vector<MatchingRule> const&, CascadeOrigin, Important important) const;
void build_rule_cache();
void build_rule_cache_if_needed() const;
DOM::Document& m_document;
struct RuleCache {
HashMap<FlyString, Vector<MatchingRule>> rules_by_id;
HashMap<FlyString, Vector<MatchingRule>> rules_by_class;
HashMap<FlyString, Vector<MatchingRule>> rules_by_tag_name;
HashMap<Selector::PseudoElement, Vector<MatchingRule>> rules_by_pseudo_element;
Vector<MatchingRule> other_rules;
};
OwnPtr<RuleCache> m_rule_cache;
void load_fonts_if_needed() const;
class FontLoader;
HashMap<String, NonnullOwnPtr<FontLoader>> m_loaded_fonts;
};
}