mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-04-25 17:25:08 +02:00
bfead0cb20
font_for_code_point() was the heaviest function in layout profiles of a YouTube page (216ms CPU out of 2900ms total). Every call walked the full cascade and ran a virtual contains_glyph() against each entry, even though the result is the same for most ASCII code points across a document. Add a 128-entry direct-mapped cache keyed by code point that stores the resolved Font pointer on first lookup. Subsequent ASCII lookups become a null check plus a load. No invalidation is needed: m_fonts is append-only, and the cascade returns the first matching font, so once an entry claims a code point, later appends cannot change the answer.
78 lines
2.4 KiB
C++
78 lines
2.4 KiB
C++
/*
|
|
* Copyright (c) 2023-2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Array.h>
|
|
#include <AK/Function.h>
|
|
#include <LibGfx/Font/Font.h>
|
|
#include <LibGfx/Font/UnicodeRange.h>
|
|
|
|
namespace Gfx {
|
|
|
|
class FontCascadeList : public RefCounted<FontCascadeList> {
|
|
public:
|
|
using SystemFontFallbackCallback = Function<RefPtr<Font const>(u32, Font const&)>;
|
|
|
|
static NonnullRefPtr<FontCascadeList> create()
|
|
{
|
|
return adopt_ref(*new FontCascadeList());
|
|
}
|
|
|
|
size_t size() const { return m_fonts.size(); }
|
|
bool is_empty() const { return m_fonts.is_empty() && !m_last_resort_font; }
|
|
Font const& first() const { return !m_fonts.is_empty() ? *m_fonts.first().font : *m_last_resort_font; }
|
|
|
|
template<typename Callback>
|
|
void for_each_font_entry(Callback callback) const
|
|
{
|
|
for (auto const& font : m_fonts)
|
|
callback(font);
|
|
}
|
|
|
|
void add(NonnullRefPtr<Font const> font);
|
|
void add(NonnullRefPtr<Font const> font, Vector<UnicodeRange> unicode_ranges);
|
|
|
|
void extend(FontCascadeList const& other);
|
|
|
|
Gfx::Font const& font_for_code_point(u32 code_point) const;
|
|
|
|
bool equals(FontCascadeList const& other) const;
|
|
|
|
struct Entry {
|
|
NonnullRefPtr<Font const> font;
|
|
struct RangeData {
|
|
// The enclosing range is the union of all Unicode ranges. Used for fast skipping.
|
|
UnicodeRange enclosing_range;
|
|
|
|
Vector<UnicodeRange> unicode_ranges;
|
|
};
|
|
Optional<RangeData> range_data;
|
|
};
|
|
|
|
void set_last_resort_font(NonnullRefPtr<Font> font) { m_last_resort_font = move(font); }
|
|
void set_system_font_fallback_callback(SystemFontFallbackCallback callback) { m_system_font_fallback_callback = move(callback); }
|
|
|
|
Font const& first_text_face() const
|
|
{
|
|
for (auto const& entry : m_fonts)
|
|
if (!entry.font->is_emoji_font())
|
|
return *entry.font;
|
|
return first();
|
|
}
|
|
|
|
private:
|
|
RefPtr<Font const> m_last_resort_font;
|
|
mutable Vector<Entry> m_fonts;
|
|
SystemFontFallbackCallback m_system_font_fallback_callback;
|
|
|
|
// OPTIMIZATION: Cache of resolved fonts for ASCII code points. Since m_fonts only grows and the cascade returns
|
|
// the first matching font, a cached hit can never become stale.
|
|
mutable Array<Font const*, 128> m_ascii_cache {};
|
|
};
|
|
|
|
}
|