STextScroller.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Layout/Clipping.h"
#include "Widgets/SCompoundWidget.h"
 
struct FTextScrollerOptions
{
    float Speed = 25.0f;
 
    float StartDelay = 0.5f;
 
    float EndDelay = 0.5f;
 
    float FadeInDelay = 0.0f;
 
    float FadeOutDelay = 0.0f;
};
 
class STextScroller : public SCompoundWidget
{
public:
    SLATE_BEGIN_ARGS(STextScroller)
        : _ScrollOrientation(Orient_Horizontal)
    {
        _Clipping = EWidgetClipping::OnDemand;
    }
        SLATE_ARGUMENT(FTextScrollerOptions, ScrollOptions)
        SLATE_ARGUMENT(EOrientation, ScrollOrientation)
        SLATE_DEFAULT_SLOT(FArguments, Content)
    SLATE_END_ARGS()
 
public:
    SLATE_API void Construct(const FArguments& InArgs);
 
    SLATE_API virtual void OnArrangeChildren(const FGeometry& AllottedGeometry, FArrangedChildren& ArrangedChildren) const override;
    SLATE_API virtual int32 OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const override;
 
    SLATE_API void ResetScrollState();
    SLATE_API void StartScrolling();
    SLATE_API void SuspendScrolling();
 
    bool IsScrollingEnabled() const { return ActiveState != EActiveState::Suspend; }
 
private:
    SLATE_API EActiveTimerReturnType OnScrollTextTick(double CurrentTime, float DeltaTime);
 
private:
    enum class EActiveState : uint8
    {
        FadeIn = 0,
        Start,
        StartWait,
        Scrolling,
        Stop,
        StopWait,
        FadeOut,
        Suspend,
    };
 
    enum class ETickerState : uint8
    {
        None = 0,
        StartTicking,
        Ticking,
        StopTicking,
    };
 
    EActiveState ActiveState = EActiveState::Start;
    ETickerState TickerState = ETickerState::None;
    float TimeElapsed = 0.0f;
    float ScrollOffset = 0.0f;
    float FontAlpha = 1.0f;
 
    TSharedPtr<FActiveTimerHandle> ActiveTimerHandle;
 
    FTextScrollerOptions ScrollOptions;
    EOrientation ScrollOrientation = Orient_Horizontal;
};