SInvalidationPanel.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "UObject/GCObject.h"
#include "Layout/Visibility.h"
#include "Layout/Geometry.h"
#include "Widgets/SWidget.h"
#include "Layout/Children.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SCompoundWidget.h"
#include "FastUpdate/SlateInvalidationRoot.h"
#include "Input/HittestGrid.h"
 
class FPaintArgs;
class FSlateRenderDataHandle;
class FSlateWindowElementList;
class SWindow;
 
 
template <>
struct TWidgetTypeTraits<class SInvalidationPanel>
{
    static constexpr bool SupportsInvalidation() { return true; }
};
 
class SInvalidationPanel : public SCompoundWidget, public FSlateInvalidationRoot
{
    SLATE_DECLARE_WIDGET_API(SInvalidationPanel, SCompoundWidget, SLATE_API)
public:
    SLATE_BEGIN_ARGS( SInvalidationPanel )
#if UE_SLATE_WITH_DYNAMIC_INVALIDATION
        : _UseDynamicInvalidation(false)
#endif
    {
        _Visibility = EVisibility::SelfHitTestInvisible;
    }
        SLATE_DEFAULT_SLOT(FArguments, Content)
#if UE_SLATE_WITH_DYNAMIC_INVALIDATION
        SLATE_ARGUMENT(bool, UseDynamicInvalidation)
#endif
#if !UE_BUILD_SHIPPING
        SLATE_ARGUMENT(FString, DebugName)
#endif
    SLATE_END_ARGS()
 
    SLATE_API SInvalidationPanel();
    SLATE_API ~SInvalidationPanel();
 
#if WITH_SLATE_DEBUGGING
    static SLATE_API bool AreInvalidationPanelsEnabled();
    static SLATE_API void EnableInvalidationPanels(bool bEnable);
#endif
    SLATE_API void Construct( const FArguments& InArgs );
 
    SLATE_API virtual FChildren* GetAllChildren() override;
 
    SLATE_API bool GetCanCache() const;
 
    SLATE_API void SetCanCache(bool InCanCache);
 
#if UE_SLATE_WITH_DYNAMIC_INVALIDATION
    SLATE_API virtual bool GetUseDynamicInvalidation() const;
 
    SLATE_API void SetUseDynamicInvalidation(bool InUseDynamicInvalidation);
 
    SLATE_API virtual bool SupportsInvalidationRecursive(bool bUseCachedValue = true) const override;
#endif
 
    //~ SWidget overrides
    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 virtual FChildren* GetChildren() override;
#if WITH_SLATE_DEBUGGING
    SLATE_API virtual FChildren* Debug_GetChildrenForReflector() override;
#endif
    //~ End SWidget
 
    SLATE_API void SetContent(const TSharedRef< SWidget >& InContent);
 
protected:
    SLATE_API virtual bool CustomPrepass(float LayoutScaleMultiplier) override;
    SLATE_API virtual bool Advanced_IsInvalidationRoot() const override;
    SLATE_API virtual const FSlateInvalidationRoot* Advanced_AsInvalidationRoot() const override;
    SLATE_API virtual TSharedRef<SWidget> GetRootWidget() override;
    SLATE_API virtual int32 PaintSlowPath(const FSlateInvalidationContext& Context) override;
 
private:
    void OnGlobalInvalidationToggled(bool bGlobalInvalidationEnabled);
    bool UpdateCachePrequisites(FSlateWindowElementList& OutDrawElements, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, int32 LayerId, const FWidgetStyle& InWidgetStyle) const;
 
private:
    mutable TSharedRef<FHittestGrid> HittestGrid;
 
    mutable TOptional<FSlateClippingState> LastClippingState;
    mutable FGeometry LastAllottedGeometry;
    mutable FVector2D LastClipRectSize;
    mutable int32 LastIncomingLayerId;
    mutable FLinearColor LastIncomingColorAndOpacity;
 
    bool bCanCache;
#if UE_SLATE_WITH_DYNAMIC_INVALIDATION
    bool bUseDynamicInvalidation;
#endif
 
    mutable bool bPaintedSinceLastPrepass;
#if SLATE_VERBOSE_NAMED_EVENTS
    FString DebugName;
    FString DebugTickName;
    FString DebugPaintName;
#endif
    mutable bool bWasCachable;
};