glyphitemcache.hxx

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 *   Licensed to the Apache Software Foundation (ASF) under one or more
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#ifndef INCLUDED_VCL_GLYPHITEMCACHE_HXX
#define INCLUDED_VCL_GLYPHITEMCACHE_HXX
 
#include <sal/types.h>
#include <vcl/dllapi.h>
 
#include <o3tl/lru_map.hxx>
#include <o3tl/hash_combine.hxx>
#include <vcl/glyphitem.hxx>
#include <vcl/metric.hxx>
#include <vcl/outdev.hxx>
#include <vcl/vclptr.hxx>
#include <tools/gen.hxx>
 
#include <optional>
 
class VCL_DLLPUBLIC SalLayoutGlyphsCache final
{
public:
    // NOTE: The lifetime of the returned value is guaranteed only until the next call
    // to any function in this class.
    const SalLayoutGlyphs* GetLayoutGlyphs(VclPtr<const OutputDevice> outputDevice,
                                           const OUString& text,
                                           const vcl::text::TextLayoutCache* layoutCache = nullptr)
    {
        return GetLayoutGlyphs(outputDevice, text, 0, text.getLength(), 0, layoutCache);
    }
    const SalLayoutGlyphs* GetLayoutGlyphs(VclPtr<const OutputDevice> outputDevice,
                                           const OUString& text, sal_Int32 nIndex, sal_Int32 nLen,
                                           tools::Long nLogicWidth = 0,
                                           const vcl::text::TextLayoutCache* layoutCache = nullptr);
    void clear();
 
    void SetCacheGlyphsWhenDoingFallbackFonts(bool bOK);
 
    static SalLayoutGlyphsCache* self();
    SalLayoutGlyphsCache(int size) // needs to be public for vcl::DeleteOnDeinit
        : mCachedGlyphs(size)
    {
    }
 
private:
    struct CachedGlyphsKey
    {
        OUString text;
        sal_Int32 index;
        sal_Int32 len;
        tools::Long logicWidth;
        FontMetric fontMetric;
        double fontScaleX;
        double fontScaleY;
        MapMode mapMode;
        bool rtl;
        bool disabledLigatures; // because of fixed pitch
        bool artificialItalic;
        bool artificialBold;
        vcl::text::ComplexTextLayoutFlags layoutMode;
        LanguageType digitLanguage;
        size_t hashValue;
        CachedGlyphsKey(const VclPtr<const OutputDevice>& dev, OUString t, sal_Int32 i, sal_Int32 l,
                        tools::Long w);
        bool operator==(const CachedGlyphsKey& other) const;
    };
    struct CachedGlyphsHash
    {
        size_t operator()(const CachedGlyphsKey& key) const { return key.hashValue; }
    };
    struct GlyphsCost
    {
        size_t operator()(const SalLayoutGlyphs&) const;
    };
    typedef o3tl::lru_map<CachedGlyphsKey, SalLayoutGlyphs, CachedGlyphsHash,
                          std::equal_to<CachedGlyphsKey>, GlyphsCost>
        GlyphsCache;
    GlyphsCache mCachedGlyphs;
    // Last temporary glyphs returned (pointer is returned, so the object needs to be kept somewhere).
    std::optional<CachedGlyphsKey> mLastTemporaryKey;
    SalLayoutGlyphs mLastTemporaryGlyphs;
    // If set, info about the last call which wanted a substring of the full text.
    std::optional<CachedGlyphsKey> mLastSubstringKey;
    bool mbCacheGlyphsWhenDoingFallbackFonts = false;
 
    SalLayoutGlyphsCache(const SalLayoutGlyphsCache&) = delete;
    SalLayoutGlyphsCache& operator=(const SalLayoutGlyphsCache&) = delete;
};
 
#endif // INCLUDED_VCL_GLYPHITEMCACHE_HXX
 
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