/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

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 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#include <sal/config.h>

#include <unx/geninst.h>

#include <font/PhysicalFontCollection.hxx>

#include <font/fontsubstitution.hxx>

#include <unx/font/fontmanager.hxx>

#include <unotools/fontdefs.hxx>

// platform specific font substitution hooks

namespace {

class FcPreMatchSubstitution

:   public vcl::font::PreMatchFontSubstitution

{

public:

    bool FindFontSubstitute( vcl::font::FontSelectPattern& ) const override;

    typedef ::std::pair<vcl::font::FontSelectPattern, vcl::font::FontSelectPattern> value_type;

private:

    typedef ::std::list<value_type> CachedFontMapType;

    mutable CachedFontMapType maCachedFontMap;

};

class FcGlyphFallbackSubstitution

:    public vcl::font::GlyphFallbackFontSubstitution

{

    // TODO: add a cache

public:

    bool FindFontSubstitute(vcl::font::FontSelectPattern&, LogicalFontInstance* pLogicalFont, OUString& rMissingCodes) const override;

};

}

void SalGenericInstance::RegisterFontSubstitutors(vcl::font::PhysicalFontCollection* pFontCollection)

{

    // register font fallback substitutions

    static FcPreMatchSubstitution aSubstPreMatch;

    pFontCollection->SetPreMatchHook( &aSubstPreMatch );

    // register glyph fallback substitutions

    static FcGlyphFallbackSubstitution aSubstFallback;

    pFontCollection->SetFallbackHook( &aSubstFallback );

}

static vcl::font::FontSelectPattern GetFcSubstitute(const vcl::font::FontSelectPattern &rFontSelData, OUString& rMissingCodes)

{

    vcl::font::FontSelectPattern aSubstituted(rFontSelData);

    FontConfigManager& rMgr = FontConfigManager::get();

    rMgr.Substitute(aSubstituted, rMissingCodes);

    return aSubstituted;

}

namespace

{

    bool uselessmatch(const vcl::font::FontSelectPattern &rOrig, const vcl::font::FontSelectPattern &rNew)

    {

        return

          (

            rOrig.maTargetName == rNew.maSearchName &&

            rOrig.GetWeight() == rNew.GetWeight() &&

            rOrig.GetItalic() == rNew.GetItalic() &&

            rOrig.GetPitch() == rNew.GetPitch() &&

            rOrig.GetWidthType() == rNew.GetWidthType()

          );

    }

    class equal

    {

    private:

        const vcl::font::FontSelectPattern& mrAttributes;

    public:

        explicit equal(const vcl::font::FontSelectPattern& rAttributes)

            : mrAttributes(rAttributes)

        {

        }

        bool operator()(const FcPreMatchSubstitution::value_type& rOther) const

            { return rOther.first == mrAttributes; }

    };

}

bool FcPreMatchSubstitution::FindFontSubstitute(vcl::font::FontSelectPattern &rFontSelData) const

{

    // We don't actually want to talk to Fontconfig at all for symbol fonts

    if( rFontSelData.IsMicrosoftSymbolEncoded() )

        return false;

    // OpenSymbol is a unicode font, but it still deserves to be treated as a symbol font

    if ( IsOpenSymbol(rFontSelData.maSearchName) )

        return false;

    //see fdo#41556 and fdo#47636

    //fontconfig can return e.g. an italic font for a non-italic input and/or

    //different fonts depending on fontsize, bold, etc settings so don't cache

    //just on the name, cache map all the input and all the output not just map

    //from original selection to output fontname

    vcl::font::FontSelectPattern& rPatternAttributes = rFontSelData;

    CachedFontMapType &rCachedFontMap = maCachedFontMap;

    CachedFontMapType::iterator itr = std::find_if(rCachedFontMap.begin(), rCachedFontMap.end(), equal(rPatternAttributes));

    if (itr != rCachedFontMap.end())

    {

        // Cached substitution

        rFontSelData = itr->second;

        if (itr != rCachedFontMap.begin())

        {

            // MRU, move it to the front

            rCachedFontMap.splice(rCachedFontMap.begin(), rCachedFontMap, itr);

        }

        return true;

    }

    OUString aDummy;

    vcl::font::FontSelectPattern aOut = GetFcSubstitute( rFontSelData, aDummy );

    if( aOut.maSearchName.isEmpty() )

        return false;

    const bool bHaveSubstitute = !uselessmatch( rFontSelData, aOut );

#if OSL_DEBUG_LEVEL >= 2

    std::ostringstream oss;

    oss << "FcPreMatchSubstitution \""

        << rFontSelData.maTargetName

        << "\" bipw="

        << rFontSelData.GetWeight()

        << rFontSelData.GetItalic()

        << rFontSelData.GetPitch()

        << rFontSelData.GetWidthType()

        << " -> ";

    if( !bHaveSubstitute )

        oss << "no substitute available.";

    else

        oss << "\""

            << aOut.maSearchName

            << "\" bipw="

            << aOut.GetWeight()

            << aOut.GetItalic()

            << aOut.GetPitch()

            << aOut.GetWidthType();

    SAL_INFO("vcl.fonts", oss.str());

#endif

    if( bHaveSubstitute )

    {

        rCachedFontMap.push_front(value_type(rFontSelData, aOut));

        // Fairly arbitrary limit in this case, but I recall measuring max 8

        // fonts as the typical max amount of fonts in medium sized documents, so make it

        // a fair chunk larger to accommodate weird documents./

        if (rCachedFontMap.size() > 256)

            rCachedFontMap.pop_back();

        rFontSelData = std::move(aOut);

    }

    return bHaveSubstitute;

}

bool FcGlyphFallbackSubstitution::FindFontSubstitute(vcl::font::FontSelectPattern& rFontSelData,

    LogicalFontInstance* /*pLogicalFont*/,

    OUString& rMissingCodes ) const

{

    // We don't actually want to talk to Fontconfig at all for symbol fonts

    if( rFontSelData.IsMicrosoftSymbolEncoded() )

        return false;

    // OpenSymbol is a unicode font, but it still deserves to be treated as a symbol font

    if ( IsOpenSymbol(rFontSelData.maSearchName) )

        return false;

    vcl::font::FontSelectPattern aOut = GetFcSubstitute( rFontSelData, rMissingCodes );

    // TODO: cache the unicode + srcfont specific result

    // FC doing it would be preferable because it knows the invariables

    // e.g. FC knows the FC rule that all Arial gets replaced by LiberationSans

    // whereas we would have to check for every size or attribute

    if( aOut.maSearchName.isEmpty() )

        return false;

    const bool bHaveSubstitute = !uselessmatch( rFontSelData, aOut );

#if OSL_DEBUG_LEVEL >= 2

    std::ostringstream oss;

    oss << "FcGFSubstitution \""

        << rFontSelData.maTargetName

        << "\" bipw="

        << rFontSelData.GetWeight()

        << rFontSelData.GetItalic()

        << rFontSelData.GetPitch()

        << rFontSelData.GetWidthType()

        << " -> ";

    if( !bHaveSubstitute )

        oss << "no substitute available.";

    else

        oss << "\""

            << aOut.maSearchName

            << "\" bipw="

            << aOut.GetWeight()

            << aOut.GetItalic()

            << aOut.GetPitch()

            << aOut.GetWidthType();

    SAL_INFO("vcl.fonts", oss.str());

#endif

    if( bHaveSubstitute )

        rFontSelData = std::move(aOut);

    return bHaveSubstitute;

}

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