kicad/include/font/fontconfig.h

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2021 Ola Rinta-Koski
 * Copyright (C) 2021-2022 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef KICAD_FONTCONFIG_H
#define KICAD_FONTCONFIG_H

#include <fontconfig/fontconfig.h>

#include <wx/string.h>
#include <vector>
#include <unordered_map>
#include <map>
#include <font/fontinfo.h>

namespace fontconfig
{

struct FONTCONFIG_PAT;

class FONTCONFIG
{
public:
    FONTCONFIG();

    static wxString Version();

    enum class FF_RESULT
    {
        FF_OK,
        FF_ERROR,
        FF_SUBSTITUTE,
        FF_MISSING_BOLD,
        FF_MISSING_ITAL,
        FF_MISSING_BOLD_ITAL
    };

    /**
     * Given a fully-qualified font name ("Times:Bold:Italic") find the closest matching font
     * and return its filepath in \a aFontFile.
     *
     * A return value of false indicates a serious error in the font system.
     */
    FF_RESULT FindFont( const wxString& aFontName, wxString& aFontFile, bool aBold, bool aItalic );

    /**
     * List the current available font families.
     *
     * @param aDesiredLang The desired language of font name to report back if available, otherwise it will fallback
     */
    void ListFonts( std::vector<std::string>& aFonts, const std::string& aDesiredLang );

private:
    std::map<std::string, FONTINFO> m_fontInfoCache;
    wxString                        m_fontCacheLastLang;

    /**
     * Matches the two rfc 3306 language entries, used for when searching for matching family names
     *
     * The overall logic is simple, either both language tags matched exactly or one tag is "single" level
     * that the other language tag contains.
     * There's nuances to language tags beyond this but font tags will most likely never be more complex than
     * say "zh-CN" or single tag "en".
     *
     * @param aSearchLang the language being searched for
     * @param aSupportedLang the language being offered
     */
    bool isLanguageMatch( const wxString& aSearchLang, const wxString& aSupportedLang );

    /**
     * Gets a list of all family name strings maped to lang
     *
     * @param aPat reference to FcPattern container
     * @param aFamStringMap Map to be populated with key, value pairs representing lang to family name
     */
    void getAllFamilyStrings( FONTCONFIG_PAT&                               aPat,
                              std::unordered_map<std::string, std::string>& aFamStringMap );

    /**
     * Gets a family name based on desired language.
     * This will fallback to english or first available string if no language matching string is found.
     *
     * @param aPat reference to FcPattern container
     * @param aDesiredLang Language to research for (RFC3066 format)
     */
    std::string getFamilyStringByLang( FONTCONFIG_PAT& APat, const wxString& aDesiredLang );

    /**
     * Wrapper of FcPatternGetString to return a std::string
     *
     * @param aPat reference to FcPattern container
     * @param aObj The fontconfig property object like FC_FAMILY, FC_STYLE, etc
     * @param aIdx The ith value associated with the property object
     */
    std::string getFcString( FONTCONFIG_PAT& aPat, const char* aObj, int aIdx );
};

} // namespace fontconfig


fontconfig::FONTCONFIG* Fontconfig();


#endif //KICAD_FONTCONFIG_H