FontMeasure.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "CoreMinimal.h"
#include "Fonts/FontTypes.h"
#include "Types/SlateVector2.h"
 
struct FSlateFontMeasureCache;
 
typedef class FLRUStringCache FMeasureCache;
struct FSlateFontMeasureCache;
 
class FSlateFontMeasure final
{
public:
 
    static SLATECORE_API TSharedRef< FSlateFontMeasure > Create( const TSharedRef<class FSlateFontCache>& FontCache );
 
public:
 
    SLATECORE_API UE::Slate::FDeprecateVector2DResult Measure( FStringView Text, const FSlateFontInfo &InFontInfo, float FontScale = 1.0f ) const;
 
    SLATECORE_API UE::Slate::FDeprecateVector2DResult Measure( const FText& Text, const FSlateFontInfo &InFontInfo, float FontScale = 1.0f ) const;
    
    SLATECORE_API UE::Slate::FDeprecateVector2DResult Measure( FStringView Text, int32 StartIndex, int32 EndIndex, const FSlateFontInfo &InFontInfo, bool IncludeKerningWithPrecedingChar = true, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindLastWholeCharacterIndexBeforeOffset( FStringView Text, const FSlateFontInfo& InFontInfo, const int32 HorizontalOffset, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindLastWholeCharacterIndexBeforeOffset( const FText& Text, const FSlateFontInfo& InFontInfo, const int32 HorizontalOffset, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindLastWholeCharacterIndexBeforeOffset( FStringView Text, int32 StartIndex, int32 EndIndex, const FSlateFontInfo& InFontInfo, const int32 HorizontalOffset, bool IncludeKerningWithPrecedingChar = true, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindFirstWholeCharacterIndexAfterOffset( FStringView Text, const FSlateFontInfo& InFontInfo, const int32 HorizontalOffset, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindFirstWholeCharacterIndexAfterOffset( const FText& Text, const FSlateFontInfo& InFontInfo, const int32 HorizontalOffset, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindFirstWholeCharacterIndexAfterOffset( FStringView Text, int32 StartIndex, int32 EndIndex, const FSlateFontInfo& InFontInfo, const int32 HorizontalOffset, bool IncludeKerningWithPrecedingChar = true, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindCharacterIndexAtOffset( FStringView Text, const FSlateFontInfo &InFontInfo, const int32 HorizontalOffset, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindCharacterIndexAtOffset( const FText& Text, const FSlateFontInfo &InFontInfo, const int32 HorizontalOffset, float FontScale = 1.0f ) const;
 
    SLATECORE_API int32 FindCharacterIndexAtOffset( FStringView Text, int32 StartIndex, int32 EndIndex, const FSlateFontInfo &InFontInfo, const int32 HorizontalOffset, bool IncludeKerningWithPrecedingChar = true, float FontScale = 1.0f ) const;
 
    SLATECORE_API uint16 GetMaxCharacterHeight( const FSlateFontInfo& InFontInfo, float FontScale = 1.0f ) const;
 
    SLATECORE_API int8 GetKerning(const FSlateFontInfo& InFontInfo, float FontScale, TCHAR PreviousCharacter, TCHAR CurrentCharacter) const;
 
    SLATECORE_API int16 GetBaseline( const FSlateFontInfo& InFontInfo, float FontScale = 1.0f ) const;
 
    SLATECORE_API void FlushCache();
 
 
private:
 
    FSlateFontMeasure( const TSharedRef<class FSlateFontCache>& InFontCache );
 
    enum ELastCharacterIndexFormat
    {
        // The last whole character before the horizontal offset
        LastWholeCharacterBeforeOffset,
        // The character directly at the offset
        CharacterAtOffset,
        // Not used
        Unused,
    };
 
    FVector2f MeasureStringInternal( FStringView Text, int32 StartIndex, int32 EndIndex, const FSlateFontInfo& InFontInfo, bool IncludeKerningWithPrecedingChar, float FontScale, int32 StopAfterHorizontalOffset, ELastCharacterIndexFormat CharIndexFormat, int32& OutLastCharacterIndex ) const;
 
    FMeasureCache* FindOrAddMeasureCache( const FSlateFontInfo& InFontInfo, const float InFontScale ) const;
 
private:
    mutable TMap<FSlateFontKey, TSharedPtr<FSlateFontMeasureCache>, FDefaultSetAllocator, FSlateFontKeyFuncs<TSharedPtr<FSlateFontMeasureCache>>> FontToMeasureCache;
 
    TSharedRef<class FSlateFontCache> FontCache;
};