ladybird/Ladybird/FontPlugin.cpp

/*
 * Copyright (c) 2022-2023, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2023, Linus Groh <linusg@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "FontPlugin.h"
#include <AK/ByteString.h>
#include <AK/String.h>
#include <LibCore/StandardPaths.h>
#include <LibGfx/Font/Emoji.h>
#include <LibGfx/Font/FontDatabase.h>

extern ByteString s_serenity_resource_root;

namespace Ladybird {

FontPlugin::FontPlugin(bool is_layout_test_mode)
    : m_is_layout_test_mode(is_layout_test_mode)
{
    // Load anything we can find in the system's font directories
    for (auto const& path : Core::StandardPaths::font_directories().release_value_but_fixme_should_propagate_errors())
        Gfx::FontDatabase::the().load_all_fonts_from_uri(MUST(String::formatted("file://{}", path)));

    Gfx::FontDatabase::set_default_font_query("Katica 10 400 0");
    Gfx::FontDatabase::set_fixed_width_font_query("Csilla 10 400 0");

    Gfx::Emoji::set_emoji_lookup_path(String::formatted("{}/res/emoji", s_serenity_resource_root).release_value_but_fixme_should_propagate_errors());

    update_generic_fonts();

    auto default_font_name = generic_font_name(Web::Platform::GenericFont::UiSansSerif);
    m_default_font = Gfx::FontDatabase::the().get(default_font_name, 12.0, 400, Gfx::FontWidth::Normal, 0);
    VERIFY(m_default_font);

    auto default_fixed_width_font_name = generic_font_name(Web::Platform::GenericFont::UiMonospace);
    m_default_fixed_width_font = Gfx::FontDatabase::the().get(default_fixed_width_font_name, 12.0, 400, Gfx::FontWidth::Normal, 0);
    VERIFY(m_default_fixed_width_font);
}

FontPlugin::~FontPlugin() = default;

Gfx::Font& FontPlugin::default_font()
{
    return *m_default_font;
}

Gfx::Font& FontPlugin::default_fixed_width_font()
{
    return *m_default_fixed_width_font;
}

void FontPlugin::update_generic_fonts()
{
    // How we choose which system font to use for each CSS font:
    // 1. Try a list of known-suitable fonts with their names hard-coded below.
    // 2. If that didn't work, fall back to Gfx::FontDatabase::default_font() (or default_fixed_width_font())

    // This is rather weird, but it's how things work right now.
    // We should eventually have a way to query the system for the default font.
    // Furthermore, we should allow overriding via some kind of configuration mechanism.

    m_generic_font_names.resize(static_cast<size_t>(Web::Platform::GenericFont::__Count));

    auto update_mapping = [&](Web::Platform::GenericFont generic_font, ReadonlySpan<FlyString> fallbacks) {
        if (m_is_layout_test_mode) {
            m_generic_font_names[static_cast<size_t>(generic_font)] = "SerenitySans"_fly_string;
            return;
        }

        RefPtr<Gfx::Font const> gfx_font;

        for (auto& fallback : fallbacks) {
            gfx_font = Gfx::FontDatabase::the().get(fallback, 16, 400, Gfx::FontWidth::Normal, 0, Gfx::Font::AllowInexactSizeMatch::Yes);
            if (gfx_font)
                break;
        }

        if (!gfx_font) {
            if (generic_font == Web::Platform::GenericFont::Monospace || generic_font == Web::Platform::GenericFont::UiMonospace)
                gfx_font = Gfx::FontDatabase::default_fixed_width_font();
            else
                gfx_font = Gfx::FontDatabase::default_font();
        }

        m_generic_font_names[static_cast<size_t>(generic_font)] = gfx_font->family();
    };

    // Fallback fonts to look for if Gfx::Font can't load expected font
    // The lists are basically arbitrary, taken from https://www.w3.org/Style/Examples/007/fonts.en.html
    Vector<FlyString> cursive_fallbacks { "Comic Sans MS"_fly_string, "Comic Sans"_fly_string, "Apple Chancery"_fly_string, "Bradley Hand"_fly_string, "Brush Script MT"_fly_string, "Snell Roundhand"_fly_string, "URW Chancery L"_fly_string };
    Vector<FlyString> fantasy_fallbacks { "Impact"_fly_string, "Luminari"_fly_string, "Chalkduster"_fly_string, "Jazz LET"_fly_string, "Blippo"_fly_string, "Stencil Std"_fly_string, "Marker Felt"_fly_string, "Trattatello"_fly_string };
    Vector<FlyString> monospace_fallbacks { "Andale Mono"_fly_string, "Courier New"_fly_string, "Courier"_fly_string, "FreeMono"_fly_string, "OCR A Std"_fly_string, "DejaVu Sans Mono"_fly_string, "Liberation Mono"_fly_string, "Csilla"_fly_string };
    Vector<FlyString> sans_serif_fallbacks { "Arial"_fly_string, "Helvetica"_fly_string, "Verdana"_fly_string, "Trebuchet MS"_fly_string, "Gill Sans"_fly_string, "Noto Sans"_fly_string, "Avantgarde"_fly_string, "Optima"_fly_string, "Arial Narrow"_fly_string, "Liberation Sans"_fly_string, "Katica"_fly_string };
    Vector<FlyString> serif_fallbacks { "Times"_fly_string, "Times New Roman"_fly_string, "Didot"_fly_string, "Georgia"_fly_string, "Palatino"_fly_string, "Bookman"_fly_string, "New Century Schoolbook"_fly_string, "American Typewriter"_fly_string, "Liberation Serif"_fly_string, "Roman"_fly_string };

    update_mapping(Web::Platform::GenericFont::Cursive, cursive_fallbacks);
    update_mapping(Web::Platform::GenericFont::Fantasy, fantasy_fallbacks);
    update_mapping(Web::Platform::GenericFont::Monospace, monospace_fallbacks);
    update_mapping(Web::Platform::GenericFont::SansSerif, sans_serif_fallbacks);
    update_mapping(Web::Platform::GenericFont::Serif, serif_fallbacks);
    update_mapping(Web::Platform::GenericFont::UiMonospace, monospace_fallbacks);
    update_mapping(Web::Platform::GenericFont::UiRounded, sans_serif_fallbacks);
    update_mapping(Web::Platform::GenericFont::UiSansSerif, sans_serif_fallbacks);
    update_mapping(Web::Platform::GenericFont::UiSerif, serif_fallbacks);
}

FlyString FontPlugin::generic_font_name(Web::Platform::GenericFont generic_font)
{
    return m_generic_font_names[static_cast<size_t>(generic_font)];
}

}