PreprocessedFontGeometry.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
 
// Forward declaration of MSDFgen types
namespace SlateMsdfgen
{
namespace msdfgen
{
class Shape;
}
typedef msdfgen::Shape FShape;
}
 
namespace UE
{
namespace Slate
{
 
class FPreprocessedFontGeometry;
 
class FPreprocessedGlyphGeometryView
{
 
public:
    friend FPreprocessedFontGeometry;
 
    FPreprocessedGlyphGeometryView()
        : Flags(0)
        , ContourCount(0)
        , ContourDataPtr(nullptr)
        , CoordinateDataPtr(nullptr)
        , ContourDataLength(0)
        , CoordinateDataLength(0)
    { }
 
    FPreprocessedGlyphGeometryView(
        uint8 InFlags,
        int32 InContourCount,
        const uint8* InContourDataPtr,
        const int16* InCoordinateDataPtr,
        int32 InContourDataLength,
        int32 InCoordinateDataLength
    );
 
    bool UpdateGeometry(SlateMsdfgen::FShape& OutMsdfgenShape) const;
 
    bool UpdateWindings(SlateMsdfgen::FShape& InOutMsdfgenShape) const;
 
    bool HasAllContoursReversedWindings() const;
 
private:
    uint8 Flags;
    int32 ContourCount;
    const uint8* ContourDataPtr;
    const int16* CoordinateDataPtr;
    int32 ContourDataLength;
    int32 CoordinateDataLength;
 
};
 
class FPreprocessedGlyphGeometry
{
public:
 
    static constexpr uint8 FLAG_REVERSE_WINDINGS = 0x01;
    static constexpr uint8 FLAG_CONTOUR_WINDINGS = 0x02;
    static constexpr uint8 FLAG_FULL_GEOMETRY = 0x04;
    static constexpr uint8 FLAG_INVERSE_Y_AXIS = 0x10;
 
    static constexpr uint8 FLAG_CONTOUR_END = 0x08;
 
    class FWindingFingerprint
    {
 
    public:
        friend FPreprocessedGlyphGeometry;
 
        explicit FWindingFingerprint(const SlateMsdfgen::FShape& MsdfgenShape);
        ~FWindingFingerprint();
 
        bool operator==(const FWindingFingerprint& Other) const;
        bool operator!=(const FWindingFingerprint& Other) const;
 
        static bool Diff(bool& OutAllDiff, TArray<uint8>& OutDiffVector, const FWindingFingerprint &A, const FWindingFingerprint &B);
 
    private:
        struct FContourFingerprint;
 
        TArray<FContourFingerprint> Contours;
 
    };
 
    class FGeometryFingerprint
    {
 
    public:
        explicit FGeometryFingerprint(const SlateMsdfgen::FShape& MsdfgenShape);
 
        bool operator==(const FGeometryFingerprint& Other) const;
        bool operator!=(const FGeometryFingerprint& Other) const;
 
    private:
        typedef TSet<TPair<int32, int32> > FContourVertices;
 
        static bool OneWayMatch(const FGeometryFingerprint& A, const FGeometryFingerprint& B);
 
        TArray<FContourVertices> Contours;
 
    };
 
    FPreprocessedGlyphGeometry();
    FPreprocessedGlyphGeometry(const FWindingFingerprint& WindingFingerprintA, const FWindingFingerprint& WindingFingerprintB);
    explicit FPreprocessedGlyphGeometry(const SlateMsdfgen::FShape& MsdfgenShape);
 
    FPreprocessedGlyphGeometryView View() const;
 
private:
    uint8 Flags;
    int32 ContourCount;
 
    TArray<uint8> ContourData;
 
    TArray<int16> CoordinateData;
 
};
 
class FPreprocessedFontGeometry
{
public:
 
    void AddGlyph(const int32 GlyphIndex, const FPreprocessedGlyphGeometryView& GlyphView);
 
    FPreprocessedGlyphGeometryView ViewGlyph(const int32 GlyphIndex) const;
 
    void SetGlobalWindingReversal(bool InGlobalWindingReversal)
    {
        GlobalWindingReversal = InGlobalWindingReversal;
    }
 
    SIZE_T GetAllocatedSize() const;
 
    SIZE_T GetDataSize() const;
 
    friend FArchive& operator<<(FArchive& Ar, FPreprocessedFontGeometry& FontGeometry);
 
private:
 
    struct FGlyphHeader
    {
        uint8 Flags;
        int32 ContourCount;
        int32 ContourDataStart;
        int32 ContourDataLength;
        int32 CoordinateDataStart;
        int32 CoordinateDataLength;
    };
 
    friend FArchive& operator<<(FArchive& Ar, FGlyphHeader& GlyphHeader) {
        return Ar
            << GlyphHeader.Flags
            << GlyphHeader.ContourCount
            << GlyphHeader.ContourDataStart
            << GlyphHeader.ContourDataLength
            << GlyphHeader.CoordinateDataStart
            << GlyphHeader.CoordinateDataLength;
    }
 
    bool GlobalWindingReversal = false;
    TMap<int32, FGlyphHeader> Glyphs;
    TArray<uint8> ContourData;
    TArray<int16> CoordinateData;
 
};
 
} // namespace Slate
} // namespace UE