ShapedTextCache.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Fonts/ShapedTextFwd.h"
#include "Fonts/SlateFontInfo.h"
#include "Framework/Text/IRun.h"
 
class FSlateFontCache;
 
struct FCachedShapedTextKey
{
public:
    FCachedShapedTextKey(const FTextRange& InTextRange, const float InScale, const FShapedTextContext& InTextContext, const FSlateFontInfo& InFontInfo)
        : TextRange(InTextRange)
        , Scale(InScale)
        , TextContext(InTextContext)
        , FontInfo(InFontInfo)
    {
    }
 
    inline bool operator==(const FCachedShapedTextKey& Other) const
    {
        return TextRange == Other.TextRange
            && Scale == Other.Scale
            && TextContext == Other.TextContext
            && FontInfo.IsIdenticalTo(Other.FontInfo);
    }
 
    inline bool operator!=(const FCachedShapedTextKey& Other) const
    {
        return !(*this == Other);
    }
 
    friend inline uint32 GetTypeHash(const FCachedShapedTextKey& Key)
    {
        uint32 KeyHash = 0;
        KeyHash = HashCombine(KeyHash, GetTypeHash(Key.TextRange));
        KeyHash = HashCombine(KeyHash, GetTypeHash(Key.Scale));
        KeyHash = HashCombine(KeyHash, GetTypeHash(Key.TextContext));
        KeyHash = HashCombine(KeyHash, GetTypeHash(Key.FontInfo));
        return KeyHash;
    }
 
    FTextRange TextRange;
    float Scale;
    FShapedTextContext TextContext;
    FSlateFontInfo FontInfo;
};
 
class FShapedTextCache
{
public:
    static FShapedTextCacheRef Create(const TSharedRef<FSlateFontCache>& InFontCache)
    {
        return MakeShared<FShapedTextCache>(FPrivateToken{}, InFontCache);
    }
 
    SLATE_API FShapedGlyphSequencePtr FindShapedText(const FCachedShapedTextKey& InKey) const;
 
    SLATE_API FShapedGlyphSequenceRef AddShapedText(const FCachedShapedTextKey& InKey, const TCHAR* InText);
    SLATE_API FShapedGlyphSequenceRef AddShapedText(const FCachedShapedTextKey& InKey, const TCHAR* InText, const TextBiDi::ETextDirection InTextDirection);
    SLATE_API FShapedGlyphSequenceRef AddShapedText(const FCachedShapedTextKey& InKey, FShapedGlyphSequenceRef InShapedText);
 
    SLATE_API FShapedGlyphSequenceRef FindOrAddShapedText(const FCachedShapedTextKey& InKey, const TCHAR* InText);
    SLATE_API FShapedGlyphSequenceRef FindOrAddShapedText(const FCachedShapedTextKey& InKey, const TCHAR* InText, const TextBiDi::ETextDirection InTextDirection);
 
    SLATE_API FShapedGlyphSequenceRef FindOrAddOverflowEllipsisText(const float InScale, const FShapedTextContext& InTextContext, const FSlateFontInfo& InFontInfo);
 
    SLATE_API void Clear();
 
    TSharedPtr<FSlateFontCache> GetFontCache() const
    {
        return FontCachePtr.Pin();
    }
 
private:
    // Private token only allows members or friends to call MakeShared
    struct FPrivateToken { explicit FPrivateToken() = default; };
 
public:
    FShapedTextCache(FPrivateToken, const TSharedRef<FSlateFontCache>& InFontCache)
        : FontCachePtr(InFontCache)
    {
    }
 
private:
    TWeakPtr<FSlateFontCache> FontCachePtr;
 
    TMap<FCachedShapedTextKey, FShapedGlyphSequencePtr> CachedShapedText;
};
 
namespace ShapedTextCacheUtil
{
 
SLATE_API FVector2D MeasureShapedText(const FShapedTextCacheRef& InShapedTextCache, const FCachedShapedTextKey& InRunKey, const FTextRange& InMeasureRange, const TCHAR* InText);
 
SLATE_API int32 FindCharacterIndexAtOffset(const FShapedTextCacheRef& InShapedTextCache, const FCachedShapedTextKey& InRunKey, const FTextRange& InTextRange, const TCHAR* InText, const int32 InHorizontalOffset);
 
SLATE_API int8 GetShapedGlyphKerning(const FShapedTextCacheRef& InShapedTextCache, const FCachedShapedTextKey& InRunKey, const int32 InGlyphIndex, const TCHAR* InText);
 
SLATE_API FShapedGlyphSequenceRef GetShapedTextSubSequence(const FShapedTextCacheRef& InShapedTextCache, const FCachedShapedTextKey& InRunKey, const FTextRange& InTextRange, const TCHAR* InText, const TextBiDi::ETextDirection InTextDirection);
 
}