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 *

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

 *

 *   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 <vcl/glyphitem.hxx>

#include <vcl/dropcache.hxx>

#include <vcl/metric.hxx>

#include <vcl/outdev.hxx>

#include <vcl/vclptr.hxx>

#include <optional>

/**

A cache for SalLayoutGlyphs objects.

Allows caching for OutputDevice::DrawText() and similar calls. Pass the text and the output device

for the call to OutputDevice::ImplLayout(). Items are cached per output device and its font.

If something more changes, call clear().

*/

class VCL_DLLPUBLIC SalLayoutGlyphsCache final : public CacheOwner

{

public:

    // NOTE: The lifetime of the returned value is guaranteed only until the next call

    // to any function in this class.

    const SalLayoutGlyphs* GetLayoutGlyphs(const 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(const VclPtr<const OutputDevice>& outputDevice,

                                           const OUString& text, sal_Int32 nIndex, sal_Int32 nLen,

                                           tools::Long nLogicWidth = 0,

                                           const vcl::text::TextLayoutCache* layoutCache = nullptr);

    const SalLayoutGlyphs* GetLayoutGlyphs(const VclPtr<const OutputDevice>& outputDevice,

                                           const OUString& text, sal_Int32 nIndex, sal_Int32 nLen,

                                           sal_Int32 nDrawMinCharPos, sal_Int32 nDrawEndCharPos,

                                           tools::Long nLogicWidth = 0,

                                           const vcl::text::TextLayoutCache* layoutCache = nullptr);

    void clear();

    /// Normally, we cannot cache glyphs when doing font fallback, because the font fallbacks

    /// can cache during the lifetime of the cache, and they are not included in the cache key.

    /// But during some processes, we can turn this on, as long as we remember to turn it off

    /// at the end.

    void SetCacheGlyphsWhenDoingFallbackFonts(bool bOK);

    static SalLayoutGlyphsCache* self();

    SalLayoutGlyphsCache(int size) // needs to be public for tools::DeleteOnDeinit

        : mCachedGlyphs(size)

    {

    }

    struct CachedGlyphsKey

    {

        OUString text;

        sal_Int32 index;

        sal_Int32 len;

        tools::Long logicWidth;

        FontMetric fontMetric;

        double fontScaleX;

        double fontScaleY;

        MapMode mapMode;

        LanguageType digitLanguage;

        vcl::text::ComplexTextLayoutFlags layoutMode;

        bool rtl : 1;

        bool disabledLigatures : 1; // because of fixed pitch

        bool artificialItalic : 1;

        bool artificialBold : 1;

        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;

    };

private:

    virtual void dropCaches() override;

    virtual void dumpState(rtl::OStringBuffer& rState) override;

    struct CachedGlyphsHash

    {

        size_t operator()(const CachedGlyphsKey& key) const { return key.hashValue; }

    };

    struct SAL_DLLPRIVATE 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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