FontCacheQt.cpp

/*
    Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
    Copyright (C) 2008 Holger Hans Peter Freyther
    Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
    Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.

    This class provides all functionality needed for loading images, style sheets and html
    pages from the web. It has a memory cache for these objects.
*/
#include "config.h"
#include "FontCache.h"

#include "Font.h"
#include "FontDescription.h"
#include "FontPlatformData.h"
#include <utility>
#include <wtf/StdLibExtras.h>
#include <wtf/text/StringHash.h>
#include <wtf/text/WTFString.h>

#include <QFont>
#include <QFontDatabase>
#include <QTextLayout>

using namespace WTF;

namespace WebCore {

void FontCache::platformInit()
{
}

static QRawFont rawFontForCharacters(const QString& string, const QRawFont& font)
{
    QTextLayout layout(string);
    layout.setRawFont(font);
    layout.beginLayout();
    layout.createLine();
    layout.endLayout();

    QList<QGlyphRun> glyphList = layout.glyphRuns();
    if (!glyphList.size())
        return QRawFont();

    // Use the first glyph run's font for the fallback
    const QGlyphRun& glyphs(glyphList.at(0));
    return glyphs.rawFont();
}

RefPtr<Font> FontCache::systemFallbackForCharacterCluster(const FontDescription&, const Font& originalFontData, IsForPlatformFont, PreferColoredFont, StringView characterCluster)
{
    QRawFont computedFont;
    QString string = characterCluster.toString();
    computedFont = rawFontForCharacters(string, originalFontData.getQtRawFont());

    if (!computedFont.isValid())
        return nullptr;
    FontPlatformData alternateFont(computedFont);
    return fontForPlatformData(alternateFont);
}

Vector<String> FontCache::systemFontFamilies()
{
    Vector<String> families;
    for (const QString& family : QFontDatabase::families())
        families.append(family);
    return families;
}

bool FontCache::isSystemFontForbiddenForEditing(const String&)
{
    return false;
}

Ref<Font> FontCache::lastResortFallbackFont(const FontDescription& fontDescription)
{
    const AtomString fallbackFamily = AtomString("helvetica"_s); // FIXME
    FontPlatformData platformData(fontDescription, fallbackFamily);
    return fontForPlatformData(platformData);
}

std::unique_ptr<FontPlatformData> FontCache::createFontPlatformData(const FontDescription& fontDescription, const AtomString& family, const FontCreationContext&, OptionSet<FontLookupOptions>)
{
    auto addResult = m_fontFamilyCache.ensure(family, [&family] {
        return QFontDatabase::hasFamily(family.string());
    });

    if (!addResult.iterator->value)
        return nullptr;
    return std::make_unique<FontPlatformData>(fontDescription, family);
}

ASCIILiteral FontCache::platformAlternateFamilyName(const String&)
{
    return {};
}

Vector<FontSelectionCapabilities> FontCache::getFontSelectionCapabilitiesInFamily(const AtomString&, AllowUserInstalledFonts)
{
    return { };
}

void FontCache::platformInvalidate()
{
}

} // namespace WebCore