SlateTextShaper.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Fonts/FontCache.h"
#include "Fonts/FontCacheFreeType.h"
#include "Fonts/FontCacheHarfBuzz.h"
#include "Fonts/FontRasterizationMode.h"
 
class FCompositeFontCache;
class FSlateFontRenderer;
class IBreakIterator;
 
class FShapedGlyphFaceData
{
public:
    FShapedGlyphFaceData(TWeakPtr<FFreeTypeFace> InFontFace, const uint32 InGlyphFlags, const float InFontSize, const float InFontScale, const float InFontSkew, const EFontRasterizationMode InRasterizationMode, const int16 InSdfPpem)
        : FontFace(MoveTemp(InFontFace))
        , GlyphFlags(InGlyphFlags)
        , FontSize(InFontSize)
        , FontScale(InFontScale)
        , BitmapRenderScale(1.0f)
        , FontSkew(InFontSkew)
        , RasterizationMode(InRasterizationMode)
        , SdfPpem(InSdfPpem)
    {
#if WITH_FREETYPE
        if (TSharedPtr<FFreeTypeFace> FontFacePin = FontFace.Pin())
        {
            BitmapRenderScale = FontFacePin->GetBitmapRenderScale();
        }
#endif  // WITH_FREETYPE
    }
 
    TWeakPtr<FFreeTypeFace> FontFace;
    uint32 GlyphFlags;
    float FontSize;
    float FontScale;
    float BitmapRenderScale;
    float FontSkew;
    EFontRasterizationMode RasterizationMode;
    int16 SdfPpem;
 
};
 
 
class FSlateTextShaper
{
public:
    FSlateTextShaper(FFreeTypeCacheDirectory* InFTCacheDirectory, FCompositeFontCache* InCompositeFontCache, FSlateFontRenderer* InFontRenderer, FSlateFontCache* InFontCache);
 
    FShapedGlyphSequenceRef ShapeBidirectionalText(const TCHAR* InText, const int32 InTextStart, const int32 InTextLen, const FSlateFontInfo& InFontInfo, const float InFontScale, const TextBiDi::ETextDirection InBaseDirection, const ETextShapingMethod TextShapingMethod);
 
    FShapedGlyphSequenceRef ShapeUnidirectionalText(const TCHAR* InText, const int32 InTextStart, const int32 InTextLen, const FSlateFontInfo& InFontInfo, const float InFontScale, const TextBiDi::ETextDirection InTextDirection, const ETextShapingMethod TextShapingMethod);
 
    void FlushCache();
 
private:
    void PerformTextShaping(const TCHAR* InText, const int32 InTextStart, const int32 InTextLen, const FSlateFontInfo& InFontInfo, const float InFontScale, const TextBiDi::ETextDirection InTextDirection, const ETextShapingMethod TextShapingMethod, TArray<FShapedGlyphEntry>& OutGlyphsToRender);
 
    FShapedGlyphSequenceRef FinalizeTextShaping(TArray<FShapedGlyphEntry> InGlyphsToRender, const FSlateFontInfo& InFontInfo, const float InFontScale, const FShapedGlyphSequence::FSourceTextRange& InSourceTextRange) const;
 
#if WITH_FREETYPE
    void PerformKerningOnlyTextShaping(const TCHAR* InText, const int32 InTextStart, const int32 InTextLen, const FSlateFontInfo& InFontInfo, const float InFontScale, TArray<FShapedGlyphEntry>& OutGlyphsToRender) const;
#endif // WITH_FREETYPE
 
#if WITH_HARFBUZZ
    void PerformHarfBuzzTextShaping(const TCHAR* InText, const int32 InTextStart, const int32 InTextLen, const FSlateFontInfo& InFontInfo, const float InFontScale, const TextBiDi::ETextDirection InTextDirection, TArray<FShapedGlyphEntry>& OutGlyphsToRender);
#endif // WITH_HARFBUZZ
 
    static bool InsertSubstituteGlyphs(const TCHAR* InText, const int32 InCharIndex, const TSharedRef<FShapedGlyphFaceData>& InShapedGlyphFaceData, const TSharedRef<FFreeTypeAdvanceCache>& AdvanceCache, TArray<FShapedGlyphEntry>& OutGlyphsToRender, const int16 InLetterSpacingScaled = 0);
 
    FFreeTypeCacheDirectory* FTCacheDirectory;
    FCompositeFontCache* CompositeFontCache;
    FSlateFontRenderer* FontRenderer;
    FSlateFontCache* FontCache;
 
    TUniquePtr<TextBiDi::ITextBiDi> TextBiDiDetection;
 
    TSharedRef<IBreakIterator> GraphemeBreakIterator;
 
#if WITH_HARFBUZZ
    FHarfBuzzFontCache HarfBuzzFontCache;
#endif // WITH_HARFBUZZ
};