FontBook.hpp

// Copyright 2019, 2020 Pokitec
// All rights reserved.
 
#pragma once
 
#include "TTauri/Text/FontDescription.hpp"
#include "TTauri/Text/Grapheme.hpp"
#include "TTauri/Text/Font.hpp"
#include "TTauri/Text/FontFamilyID.hpp"
#include "TTauri/Text/FontID.hpp"
#include "TTauri/Text/FontGraphemeID.hpp"
#include "TTauri/Text/FontGlyphIDs.hpp"
#include "TTauri/Foundation/URL.hpp"
#include "TTauri/Foundation/attributes.hpp"
#include <limits>
#include <array>
#include <new>
 
 
namespace tt {
 
class FontBook {
    struct FontEntry {
        URL url;
        FontDescription description;
        mutable std::unique_ptr<Font> font;
        std::vector<FontID> fallbacks;
 
        FontEntry(URL url, FontDescription description) noexcept : url(std::move(url)), description(std::move(description)), font(), fallbacks() {}
    };
 
 
    std::unordered_map<std::string,FontFamilyID> family_names;
 
    std::unordered_map<std::string,std::string> family_name_fallback_chain;
 
    std::vector<std::array<FontID,FontVariant::max()>> font_variants;
 
    std::vector<FontEntry> font_entries;
 
    mutable std::unordered_map<std::string,FontFamilyID> family_name_cache;
 
    mutable std::unordered_map<FontGraphemeID, FontGlyphIDs> glyph_cache;
 
public:
    FontBook(std::vector<URL> const &font_directories);
 
    FontID register_font(URL url, bool post_process=true);
 
    void post_process() noexcept;
 
 
    [[nodiscard]] FontFamilyID find_family(std::string_view family_name) const noexcept;
 
    [[nodiscard]] FontFamilyID register_family(std::string_view family_name) noexcept;
 
    [[nodiscard]] FontID find_font(FontFamilyID family_id, FontVariant variant) const noexcept;
 
    [[nodiscard]] FontID find_font(FontFamilyID family_id, FontWeight weight, bool italic) const noexcept;
 
    [[nodiscard]] FontID find_font(std::string_view family_name, FontWeight weight, bool italic) const noexcept;
 
    [[nodiscard]] Font const &get_font(FontID font_id) const noexcept;
 
    [[nodiscard]] FontGlyphIDs find_glyph(FontID font_id, Grapheme grapheme) const noexcept;
 
private:
 
    void calculate_fallback_fonts(FontEntry &entry, std::function<bool(FontDescription const&,FontDescription const&)> predicate) noexcept;
 
    [[nodiscard]] FontGlyphIDs find_glyph_actual(FontID font_id, Grapheme grapheme) const noexcept;
 
    //void morph_glyphs(glyph_array &glyphs) const noexcept;
 
    //void atlas_lookup(glyph &glyph) noexcept;
 
    //void atlas_lookup(glyph_array &glyphs) noexcept;
 
    //void kern_glyphs(glyph_array &glyphs) const noexcept;
 
    [[nodiscard]] std::string const &find_fallback_family_name(std::string const &name) const noexcept;
 
    void create_family_name_fallback_chain() noexcept;
 
};
 
inline FontBook *fontBook;
 
}