LogicalFontInstance.hxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * 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 .
 */
 
#pragma once
 
#include <sal/config.h>
 
#include <basegfx/polygon/b2dpolypolygon.hxx>
#include <o3tl/hash_combine.hxx>
#include <rtl/ref.hxx>
#include <salhelper/simplereferenceobject.hxx>
#include <tools/gen.hxx>
#include <tools/fontenum.hxx>
#include <tools/degree.hxx>
 
#include <font/FontSelectPattern.hxx>
#include <font/FontMetricData.hxx>
#include <glyphid.hxx>
 
#include <optional>
#include <unordered_map>
#include <memory>
 
#include <hb.h>
 
class ConvertChar;
class ImplFontCache;
 
constexpr float ARTIFICIAL_ITALIC_MATRIX_XX = 1 << 16;
constexpr float ARTIFICIAL_ITALIC_MATRIX_XY = (1 << 16) / 3.f;
constexpr float ARTIFICIAL_ITALIC_SKEW = ARTIFICIAL_ITALIC_MATRIX_XY / ARTIFICIAL_ITALIC_MATRIX_XX;
 
// extend std namespace to add custom hash needed for LogicalFontInstance
 
namespace std
{
template <> struct hash<pair<sal_UCS4, FontWeight>>
{
    size_t operator()(const pair<sal_UCS4, FontWeight>& rData) const
    {
        std::size_t seed = 0;
        o3tl::hash_combine(seed, rData.first);
        o3tl::hash_combine(seed, rData.second);
        return seed;
    }
};
}
 
// TODO: allow sharing of metrics for related fonts
 
class VCL_PLUGIN_PUBLIC LogicalFontInstance : public salhelper::SimpleReferenceObject
{
    // just declaring the factory function doesn't work AKA
    // friend LogicalFontInstance* PhysicalFontFace::CreateFontInstance(const FontSelectPattern&) const;
    friend class vcl::font::PhysicalFontFace;
    friend class ImplFontCache;
 
public: // TODO: make data members private
    virtual ~LogicalFontInstance() override;
 
    FontMetricDataRef mxFontMetric; // Font attributes
    const ConvertChar* mpConversion; // used e.g. for StarBats->StarSymbol
 
    tools::Long mnLineHeight;
    Degree10 mnOwnOrientation; // text angle if lower layers don't rotate text themselves
    Degree10 mnOrientation; // text angle in 3600 system
    bool mbInit; // true if maFontMetric member is valid
 
    void AddFallbackForUnicode(sal_UCS4 cChar, FontWeight eWeight, const OUString& rFontName,
                               bool bEmbolden, const ItalicMatrix& rMatrix);
    bool GetFallbackForUnicode(sal_UCS4 cInChar, FontWeight eInWeight, OUString* pOutFontName,
                               bool* pOutEmbolden, ItalicMatrix* pOutItalicMatrix) const;
    void IgnoreFallbackForUnicode(sal_UCS4, FontWeight eWeight, std::u16string_view rFontName);
 
    inline hb_font_t* GetHbFont();
    bool IsGraphiteFont();
    // NeedOffsetCorrection: Return if the font need offset correction in TTB direction.
    // nYOffset is the original offset. It is used to check if the correction is necessary.
    bool NeedOffsetCorrection(sal_Int32 nYOffset);
    void SetAverageWidthFactor(double nFactor) { m_nAveWidthFactor = std::abs(nFactor); }
    double GetAverageWidthFactor() const { return m_nAveWidthFactor; }
    const vcl::font::FontSelectPattern& GetFontSelectPattern() const { return m_aFontSelData; }
 
    const vcl::font::PhysicalFontFace* GetFontFace() const { return m_pFontFace.get(); }
    vcl::font::PhysicalFontFace* GetFontFace() { return m_pFontFace.get(); }
    const ImplFontCache* GetFontCache() const { return mpFontCache; }
 
    bool GetGlyphBoundRect(sal_GlyphId, tools::Rectangle&, bool) const;
    virtual bool GetGlyphOutline(sal_GlyphId, basegfx::B2DPolyPolygon&, bool) const = 0;
    basegfx::B2DPolyPolygon GetGlyphOutlineUntransformed(sal_GlyphId) const;
 
    sal_GlyphId GetGlyphIndex(uint32_t, uint32_t = 0) const;
 
    double GetGlyphWidth(sal_GlyphId, bool = false, bool = true) const;
 
    double GetKashidaWidth() const;
 
    void GetScale(double* nXScale, double* nYScale) const;
 
    bool NeedsArtificialItalic() const;
    bool NeedsArtificialBold() const;
 
protected:
    explicit LogicalFontInstance(const vcl::font::PhysicalFontFace&,
                                 const vcl::font::FontSelectPattern&);
 
    hb_font_t* InitHbFont();
    virtual void ImplInitHbFont(hb_font_t*) {}
 
private:
    hb_font_t* GetHbFontUntransformed() const;
 
    struct MapEntry
    {
        OUString sFontName;
        bool bEmbolden;
        ItalicMatrix aItalicMatrix;
    };
    // cache of Unicode characters and replacement font names and attributes
    // TODO: a fallback map can be shared with many other ImplFontEntries
    // TODO: at least the ones which just differ in orientation, stretching or height
    typedef ::std::unordered_map<::std::pair<sal_UCS4, FontWeight>, MapEntry> UnicodeFallbackList;
    UnicodeFallbackList maUnicodeFallbackList;
    mutable ImplFontCache* mpFontCache;
    const vcl::font::FontSelectPattern m_aFontSelData;
    hb_font_t* m_pHbFont;
    mutable hb_font_t* m_pHbFontUntransformed = nullptr;
    double m_nAveWidthFactor;
    rtl::Reference<vcl::font::PhysicalFontFace> m_pFontFace;
    std::optional<bool> m_xbIsGraphiteFont;
 
    enum class FontFamilyEnum
    {
        Unclassified,
        DFKaiSB
    };
 
    // The value is initialized and used in NeedOffsetCorrection().
    std::optional<FontFamilyEnum> m_xeFontFamilyEnum;
 
    mutable hb_draw_funcs_t* m_pHbDrawFuncs = nullptr;
    basegfx::B2DPolygon m_aDrawPolygon;
};
 
inline hb_font_t* LogicalFontInstance::GetHbFont()
{
    if (!m_pHbFont)
        m_pHbFont = InitHbFont();
    return m_pHbFont;
}
 
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