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diff --git a/vcl/inc/font/LogicalFontInstance.hxx b/vcl/inc/font/LogicalFontInstance.hxx
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+++ b/vcl/inc/font/LogicalFontInstance.hxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * 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 .
+ */
+
+#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 <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;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */