C++ FPaintArgs类代码示例

void FCachedWidgetNode::Initialize(const FPaintArgs& Args, TSharedRef<SWidget> InWidget, const FGeometry& InGeometry, const FSlateRect& InClippingRect)
{
	Widget = InWidget;
	Geometry = InGeometry;
	ClippingRect = InClippingRect;
	WindowOffset = Args.GetWindowToDesktopTransform();
	RecordedVisibility = Args.GetLastRecordedVisibility();
	LastRecordedHittestIndex = 0;

	if ( RecordedVisibility.AreChildrenHitTestVisible() )
	{
		RecordedVisibility = InWidget->GetVisibility();
	}

	Children.Reset();
}

/**
 * This widget was created before render transforms existed for each widget, and it chose to apply the render transform AFTER the layout transform.
 * This means leveraging the render transform of FGeometry would be expensive, as we would need to use Concat(LayoutTransform, RenderTransform, Inverse(LayoutTransform).
 * Instead, we maintain the old way of doing it by modifying the AllottedGeometry only during rendering to append the widget's implied RenderTransform to the existing LayoutTransform.
 */
int32 SFxWidget::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	// Convert the 0..1 origin into local space extents.
	const FVector2D ScaleOrigin = RenderScaleOrigin.Get() * AllottedGeometry.Size;
	const FVector2D Offset = VisualOffset.Get() * AllottedGeometry.Size;
	// create the render transform as a scale around ScaleOrigin and offset it by Offset.
	const auto RenderTransform = Concatenate(Inverse(ScaleOrigin), RenderScale.Get(), ScaleOrigin, Offset);
	// This will append the render transform to the layout transform, and we only use it for rendering.
	FGeometry ModifiedGeometry = AllottedGeometry.MakeChild(AllottedGeometry.Size, RenderTransform);
	
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	this->ArrangeChildren(ModifiedGeometry, ArrangedChildren);

	// There may be zero elements in this array if our child collapsed/hidden
	if( ArrangedChildren.Num() > 0 )
	{
		// We can only have one direct descendant.
		check( ArrangedChildren.Num() == 1 );
		const FArrangedWidget& TheChild = ArrangedChildren[0];

		// SFxWidgets are able to ignore parent clipping.
		const FSlateRect ChildClippingRect = (bIgnoreClipping.Get())
			? ModifiedGeometry.GetClippingRect()
			: MyClippingRect.IntersectionWith(ModifiedGeometry.GetClippingRect());

		FWidgetStyle CompoundedWidgetStyle = FWidgetStyle(InWidgetStyle)
			.BlendColorAndOpacityTint(ColorAndOpacity.Get())
			.SetForegroundColor( ForegroundColor );

		return TheChild.Widget->Paint( Args.WithNewParent(this), TheChild.Geometry, ChildClippingRect, OutDrawElements, LayerId + 1, CompoundedWidgetStyle, ShouldBeEnabled( bParentEnabled ) );
	}
	return LayerId;

}

int32 SPanel::PaintArrangedChildren( const FPaintArgs& Args, const FArrangedChildren& ArrangedChildren, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled  ) const
{
	// Because we paint multiple children, we must track the maximum layer id that they produced in case one of our parents
	// wants to an overlay for all of its contents.
	int32 MaxLayerId = LayerId;

	const FPaintArgs NewArgs = Args.WithNewParent(this);

	for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
	{
		const FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];

		bool bWereOverlapping;
		FSlateRect ChildClipRect = MyClippingRect.IntersectionWith(CurWidget.Geometry.GetClippingRect(), bWereOverlapping);
		
		if ( bWereOverlapping )
		{
			const int32 CurWidgetsMaxLayerId = CurWidget.Widget->Paint(NewArgs, CurWidget.Geometry, ChildClipRect, OutDrawElements, LayerId, InWidgetStyle, ShouldBeEnabled(bParentEnabled));
			MaxLayerId = FMath::Max(MaxLayerId, CurWidgetsMaxLayerId);
		}		
		
	}
	
	return MaxLayerId;
}

/** SWidget Interface */
int32 SSequencerSectionAreaView::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	ArrangeChildren(AllottedGeometry, ArrangedChildren);

	if( SectionAreaNode.IsValid() )
	{
		// Draw a region around the entire section area
		FSlateDrawElement::MakeBox( 
			OutDrawElements, 
			LayerId,
			AllottedGeometry.ToPaintGeometry(),
			BackgroundBrush,
			MyClippingRect,
			ESlateDrawEffect::None,
			SequencerSectionAreaConstants::BackgroundColor
			);
	}

	for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
	{
		FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
		FSlateRect ChildClipRect = MyClippingRect.IntersectionWith( CurWidget.Geometry.GetClippingRect() );
		const int32 CurWidgetsMaxLayerId = CurWidget.Widget->Paint( Args.WithNewParent(this), CurWidget.Geometry, ChildClipRect, OutDrawElements, LayerId+1, InWidgetStyle, ShouldBeEnabled( bParentEnabled ) );
	}

	return LayerId+1;
}

int32 SDockingTabWell::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	// When we are dragging a tab, it must be painted on top of the other tabs, so we cannot
	// just reuse the Panel's default OnPaint.


	// The TabWell has no visualization of its own; it just visualizes its child tabs.
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

	// Because we paint multiple children, we must track the maximum layer id that they produced in case one of our parents
	// wants to an overlay for all of its contents.
	int32 MaxLayerId = LayerId;

	TSharedPtr<SDockTab> ForegroundTab = GetForegroundTab();
	FArrangedWidget* ForegroundTabGeometry = NULL;
	
	// Draw all inactive tabs first
	for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
	{
		FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
		if (CurWidget.Widget == ForegroundTab)
		{
			ForegroundTabGeometry = &CurWidget;
		}
		else
		{
			FSlateRect ChildClipRect = MyClippingRect.IntersectionWith( CurWidget.Geometry.GetClippingRect() );
			const int32 CurWidgetsMaxLayerId = CurWidget.Widget->Paint( Args.WithNewParent(this), CurWidget.Geometry, ChildClipRect, OutDrawElements, MaxLayerId, InWidgetStyle, ShouldBeEnabled( bParentEnabled ) );
			MaxLayerId = FMath::Max( MaxLayerId, CurWidgetsMaxLayerId );
		}
	}

	// Draw active tab in front
	if (ForegroundTab != TSharedPtr<SDockTab>())
	{
		FSlateRect ChildClipRect = MyClippingRect.IntersectionWith( ForegroundTabGeometry->Geometry.GetClippingRect() );
		const int32 CurWidgetsMaxLayerId = ForegroundTabGeometry->Widget->Paint( Args.WithNewParent(this), ForegroundTabGeometry->Geometry, ChildClipRect, OutDrawElements, MaxLayerId, InWidgetStyle, ShouldBeEnabled( bParentEnabled ) );
		MaxLayerId = FMath::Max( MaxLayerId, CurWidgetsMaxLayerId );
	}

	return MaxLayerId;
}

int32 SGridPanel::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
    FArrangedChildren ArrangedChildren(EVisibility::All);
    this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

    // Because we paint multiple children, we must track the maximum layer id that they produced in case one of our parents
    // wants to an overlay for all of its contents.
    int32 MaxLayerId = LayerId;

    // We need to iterate over slots, because slots know the GridLayers. This isn't available in the arranged children.
    // Some slots do not show up (they are hidden/collapsed). We need a 2nd index to skip over them.
    //
    // GridLayers must ensure that everything in LayerN is below LayerN+1. In other words,
    // every grid layer group must start at the current MaxLayerId (similar to how SOverlay works).
    int32 LastGridLayer = 0;
    for (int32 ChildIndex = 0; ChildIndex < Slots.Num(); ++ChildIndex)
    {
        FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
        if (CurWidget.Widget->GetVisibility().IsVisible())
        {
            const FSlot& CurSlot = Slots[ChildIndex];

            FSlateRect ChildClipRect = MyClippingRect.IntersectionWith( CurWidget.Geometry.GetClippingRect() );

            if ( LastGridLayer != CurSlot.LayerParam )
            {
                // We starting a new grid layer group?
                LastGridLayer = CurSlot.LayerParam;
                // Ensure that everything here is drawn on top of
                // previously drawn grid content.
                LayerId = MaxLayerId+1;
            }

            const int32 CurWidgetsMaxLayerId = CurWidget.Widget->Paint(
                                                   Args.WithNewParent(this),
                                                   CurWidget.Geometry,
                                                   ChildClipRect,
                                                   OutDrawElements,
                                                   LayerId,
                                                   InWidgetStyle,
                                                   ShouldBeEnabled( bParentEnabled )
                                               );

            MaxLayerId = FMath::Max( MaxLayerId, CurWidgetsMaxLayerId );
        }
    }

//#define LAYOUT_DEBUG

#ifdef LAYOUT_DEBUG
    LayerId = LayoutDebugPaint( AllottedGeometry, MyClippingRect, OutDrawElements, LayerId );
#endif

    return MaxLayerId;
}

int32 SMenuAnchor::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	FArrangedChildren ArrangedChildren( EVisibility::Visible );
	ArrangeChildren( AllottedGeometry, ArrangedChildren );
	
	// There may be zero elements in this array if our child collapsed/hidden
	if ( ArrangedChildren.Num() > 0 )
	{
		const FArrangedWidget& FirstChild = ArrangedChildren[0];

		// In the case where the user doesn't provide content to the menu anchor, the null widget
		// wont appear in the visible set of arranged children, so only immediately paint the first child,
		// if it's visible and matches the first slot content.
		const bool bHasArrangedAnchorContent = FirstChild.Widget == Children[0].GetWidget();
		if ( bHasArrangedAnchorContent )
		{
			const FSlateRect ChildClippingRect = AllottedGeometry.GetClippingRect().IntersectionWith(MyClippingRect);
			LayerId = FirstChild.Widget->Paint(Args.WithNewParent(this), FirstChild.Geometry, ChildClippingRect, OutDrawElements, LayerId + 1, InWidgetStyle, ShouldBeEnabled(bParentEnabled));
		}

		const bool bIsOpen = IsOpen();

		if ( bIsOpen )
		{
			// In the case where the anchor content is present and visible, it's the 1 index child, in the case
			// where the anchor content is invisible, it's the 0 index child.
			FArrangedWidget* PopupChild = nullptr;
			if ( bHasArrangedAnchorContent && ArrangedChildren.Num() > 1 )
			{
				PopupChild = &ArrangedChildren[1];
			}
			else if ( !bHasArrangedAnchorContent && ArrangedChildren.Num() == 1 )
			{
				PopupChild = &ArrangedChildren[0];
			}

			if ( PopupChild != nullptr )
			{
				 OutDrawElements.QueueDeferredPainting(
					FSlateWindowElementList::FDeferredPaint(PopupChild->Widget, Args, PopupChild->Geometry, MyClippingRect, InWidgetStyle, bParentEnabled));
			}
		} 
	}

	return LayerId;
}

int32 SBox::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	// An SBox just draws its only child
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

	// Maybe none of our children are visible
	if( ArrangedChildren.Num() > 0 )
	{
		check( ArrangedChildren.Num() == 1 );
		FArrangedWidget& TheChild = ArrangedChildren[0];

		const FSlateRect ChildClippingRect = AllottedGeometry.GetClippingRect().InsetBy( ChildSlot.SlotPadding.Get() * AllottedGeometry.Scale ).IntersectionWith(MyClippingRect);

		return TheChild.Widget->Paint( Args.WithNewParent(this), TheChild.Geometry, ChildClippingRect, OutDrawElements, LayerId, InWidgetStyle, ShouldBeEnabled( bParentEnabled ) );
	}
	return LayerId;
}

int32 SConstraintCanvas::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

	// Because we paint multiple children, we must track the maximum layer id that they produced in case one of our parents
	// wants to an overlay for all of its contents.
	int32 MaxLayerId = LayerId;

	for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
	{
		FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
		FSlateRect ChildClipRect = MyClippingRect.IntersectionWith(CurWidget.Geometry.GetClippingRect());
		const int32 CurWidgetsMaxLayerId = CurWidget.Widget->Paint( Args.WithNewParent(this), CurWidget.Geometry, ChildClipRect, OutDrawElements, MaxLayerId + 1, InWidgetStyle, ShouldBeEnabled(bParentEnabled));

		MaxLayerId = FMath::Max(MaxLayerId, CurWidgetsMaxLayerId);
	}

	return MaxLayerId;
}

int32 SSequencerTrackArea::OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	ArrangeChildren(AllottedGeometry, ArrangedChildren);

	for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
	{
		FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
		FSlateRect ChildClipRect = MyClippingRect.IntersectionWith( CurWidget.Geometry.GetClippingRect() );
		const int32 ThisWidgetLayerId = CurWidget.Widget->Paint( Args.WithNewParent(this), CurWidget.Geometry, ChildClipRect, OutDrawElements, LayerId + 1, InWidgetStyle, ShouldBeEnabled( bParentEnabled ) );

		LayerId = FMath::Max(LayerId, ThisWidgetLayerId);
	}

	auto SequencerPin = SequencerWidget.Pin();
	if (SequencerPin.IsValid())
	{
		return SequencerPin->GetEditTool().OnPaint(AllottedGeometry, MyClippingRect, OutDrawElements, LayerId + 1);
	}

	return LayerId;
}

int32 SResponsiveGridPanel::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	FArrangedChildren ArrangedChildren(EVisibility::All);
	this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

	// Because we paint multiple children, we must track the maximum layer id that they produced in case one of our parents
	// wants to an overlay for all of its contents.
	int32 MaxLayerId = LayerId;

	// We need to iterate over slots, because slots know the GridLayers. This isn't available in the arranged children.
	// Some slots do not show up (they are hidden/collapsed). We need a 2nd index to skip over them.
	 
	for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
	{
		FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
		if (CurWidget.Widget->GetVisibility().IsVisible())
		{
			FSlateRect ChildClipRect = MyClippingRect.IntersectionWith( CurWidget.Geometry.GetClippingRect() );

			const int32 CurWidgetsMaxLayerId = CurWidget.Widget->Paint(
				Args.WithNewParent(this),
				CurWidget.Geometry,
				ChildClipRect,
				OutDrawElements,
				LayerId,
				InWidgetStyle,
				ShouldBeEnabled( bParentEnabled )
			);
			
			MaxLayerId = FMath::Max( MaxLayerId, CurWidgetsMaxLayerId );
		}
	}

#ifdef LAYOUT_DEBUG
	LayerId = LayoutDebugPaint( AllottedGeometry, MyClippingRect, OutDrawElements, LayerId );
#endif

	return MaxLayerId;
}

int32 SPopup::OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const
{
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

	// There may be zero elements in this array if our child collapsed/hidden
	if (ArrangedChildren.Num() > 0)
	{
		check(ArrangedChildren.Num() == 1);
		FArrangedWidget& TheChild = ArrangedChildren[0];

		FWidgetStyle CompoundedWidgetStyle = FWidgetStyle(InWidgetStyle)
			.BlendColorAndOpacityTint(ColorAndOpacity.Get())
			.SetForegroundColor(GetForegroundColor());

		// An SPopup just queues up its children to be painted after everything in this window is done painting.
		OutDrawElements.QueueDeferredPainting(
			FSlateWindowElementList::FDeferredPaint(TheChild.Widget, Args.WithNewParent(this), TheChild.Geometry, MyClippingRect, CompoundedWidgetStyle, ShouldBeEnabled(bParentEnabled))
		);
	}
	return LayerId;
}

int32 SWeakWidget::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	// Just draw the children.
	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	this->ArrangeChildren(AllottedGeometry, ArrangedChildren);

	// There may be zero elements in this array if our child collapsed/hidden
	if( ArrangedChildren.Num() > 0 )
	{
		check( ArrangedChildren.Num() == 1 );
		FArrangedWidget& TheChild = ArrangedChildren[0];

		return TheChild.Widget->Paint( 
			Args.WithNewParent(this), 
			TheChild.Geometry, 
			MyClippingRect, 
			OutDrawElements, 
			LayerId + 1,
			InWidgetStyle, 
			ShouldBeEnabled( bParentEnabled ) );
	}
	return LayerId;
}

int32 SInvalidationPanel::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
	if ( GetCanCache() )
	{
		const bool bWasCachingNeeded = bNeedsCaching;

		if ( bNeedsCaching )
		{
			SInvalidationPanel* MutableThis = const_cast<SInvalidationPanel*>( this );

			// Always set the caching flag to false first, during the paint / tick pass we may change something
			// to volatile and need to re-cache.
			bNeedsCaching = false;

			bIsInvalidating = true;

			if ( !CachedWindowElements.IsValid() || CachedWindowElements->GetWindow() != OutDrawElements.GetWindow() )
			{
				CachedWindowElements = MakeShareable(new FSlateWindowElementList(OutDrawElements.GetWindow()));
			}
			else
			{
				CachedWindowElements->Reset();
			}

			// Reset the cached node pool index so that we effectively reset the pool.
			LastUsedCachedNodeIndex = 0;

			RootCacheNode = CreateCacheNode();
			RootCacheNode->Initialize(Args, SharedThis(MutableThis), AllottedGeometry, MyClippingRect);

			//TODO: When SWidget::Paint is called don't drag self if volatile, and we're doing a cache pass.
			CachedMaxChildLayer = SCompoundWidget::OnPaint(
				Args.EnableCaching(SharedThis(MutableThis), RootCacheNode, true, false),
				AllottedGeometry,
				MyClippingRect,
				*CachedWindowElements.Get(),
				LayerId,
				InWidgetStyle,
				bParentEnabled);

			if ( bCacheRelativeTransforms )
			{
				CachedAbsolutePosition = AllottedGeometry.Position;
			}

			LastLayerId = LayerId;
			LastHitTestIndex = Args.GetLastHitTestIndex();

			bIsInvalidating = false;
		}

		// The hit test grid is actually populated during the initial cache phase, so don't bother
		// recording the hit test geometry on the same frame that we regenerate the cache.
		if ( bWasCachingNeeded == false )
		{
			RootCacheNode->RecordHittestGeometry(Args.GetGrid(), Args.GetLastHitTestIndex());
		}

		if ( bCacheRelativeTransforms )
		{
			FVector2D DeltaPosition = AllottedGeometry.Position - CachedAbsolutePosition;

			const TArray<FSlateDrawElement>& CachedElements = CachedWindowElements->GetDrawElements();
			const int32 CachedElementCount = CachedElements.Num();
			for ( int32 Index = 0; Index < CachedElementCount; Index++ )
			{
				const FSlateDrawElement& LocalElement = CachedElements[Index];
				FSlateDrawElement AbsElement = LocalElement;

				AbsElement.SetPosition(LocalElement.GetPosition() + DeltaPosition);
				AbsElement.SetClippingRect(LocalElement.GetClippingRect().OffsetBy(DeltaPosition));

				OutDrawElements.AddItem(AbsElement);
			}
		}
		else
		{
			OutDrawElements.AppendDrawElements(CachedWindowElements->GetDrawElements());
		}

		int32 OutMaxChildLayer = CachedMaxChildLayer;

		// Paint the volatile elements
		if ( CachedWindowElements.IsValid() )
		{
			OutMaxChildLayer = FMath::Max(CachedMaxChildLayer, CachedWindowElements->PaintVolatile(OutDrawElements));
		}

#if !UE_BUILD_SHIPPING

		if ( IsInvalidationDebuggingEnabled() )
		{
			// Draw a green or red border depending on if we were invalidated this frame.
			{
				check(Args.IsCaching() == false);
				//const bool bShowOutlineAsCached = Args.IsCaching() || bWasCachingNeeded == false;
				const FLinearColor DebugTint = bWasCachingNeeded ? FLinearColor::Red : FLinearColor::Green;

				FGeometry ScaledOutline = AllottedGeometry.MakeChild(FVector2D(0, 0), AllottedGeometry.GetLocalSize() * AllottedGeometry.Scale, Inverse(AllottedGeometry.Scale));
//.........这里部分代码省略.........

int32 SGraphPanel::OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const
{
#if SLATE_HD_STATS
	SCOPE_CYCLE_COUNTER( STAT_SlateOnPaint_SGraphPanel );
#endif

	CachedAllottedGeometryScaledSize = AllottedGeometry.Size * AllottedGeometry.Scale;

	//Style used for objects that are the same between revisions
	FWidgetStyle FadedStyle = InWidgetStyle;
	FadedStyle.BlendColorAndOpacityTint(FLinearColor(0.45f,0.45f,0.45f,0.45f));

	// First paint the background
	const UEditorExperimentalSettings& Options = *GetDefault<UEditorExperimentalSettings>();

	const FSlateBrush* BackgroundImage = FEditorStyle::GetBrush(TEXT("Graph.Panel.SolidBackground"));
	PaintBackgroundAsLines(BackgroundImage, AllottedGeometry, MyClippingRect, OutDrawElements, LayerId);

	const float ZoomFactor = AllottedGeometry.Scale * GetZoomAmount();

	FArrangedChildren ArrangedChildren(EVisibility::Visible);
	ArrangeChildNodes(AllottedGeometry, ArrangedChildren);

	// Determine some 'global' settings based on current LOD
	const bool bDrawShadowsThisFrame = GetCurrentLOD() > EGraphRenderingLOD::LowestDetail;

	// Because we paint multiple children, we must track the maximum layer id that they produced in case one of our parents
	// wants to an overlay for all of its contents.

	// Save LayerId for comment boxes to ensure they always appear below nodes & wires
	const int32 CommentNodeShadowLayerId = LayerId++;
	const int32 CommentNodeLayerId = LayerId++;

	// Save a LayerId for wires, which appear below nodes but above comments
	// We will draw them later, along with the arrows which appear above nodes.
	const int32 WireLayerId = LayerId++;

	const int32 NodeShadowsLayerId = LayerId;
	const int32 NodeLayerId = NodeShadowsLayerId + 1;
	int32 MaxLayerId = NodeLayerId;

	const FVector2D NodeShadowSize = GetDefault<UGraphEditorSettings>()->GetShadowDeltaSize();
	const UEdGraphSchema* Schema = GraphObj->GetSchema();

	// Draw the child nodes
	{
		// When drawing a marquee, need a preview of what the selection will be.
		const FGraphPanelSelectionSet* SelectionToVisualize = &(SelectionManager.SelectedNodes);
		FGraphPanelSelectionSet SelectionPreview;
		if ( Marquee.IsValid() )
		{			
			ApplyMarqueeSelection(Marquee, SelectionManager.SelectedNodes, SelectionPreview);
			SelectionToVisualize = &SelectionPreview;
		}

		// Context for rendering node infos
		FKismetNodeInfoContext Context(GraphObj);

		TArray<FGraphDiffControl::FNodeMatch> NodeMatches;
		for (int32 ChildIndex = 0; ChildIndex < ArrangedChildren.Num(); ++ChildIndex)
		{
			FArrangedWidget& CurWidget = ArrangedChildren[ChildIndex];
			TSharedRef<SGraphNode> ChildNode = StaticCastSharedRef<SGraphNode>(CurWidget.Widget);
			
			// Examine node to see what layers we should be drawing in
			int32 ShadowLayerId = NodeShadowsLayerId;
			int32 ChildLayerId = NodeLayerId;

			// If a comment node, draw in the dedicated comment slots
			{
				UObject* NodeObj = ChildNode->GetObjectBeingDisplayed();
				if (NodeObj && NodeObj->IsA(UEdGraphNode_Comment::StaticClass()))
				{
					ShadowLayerId = CommentNodeShadowLayerId;
					ChildLayerId = CommentNodeLayerId;
				}
			}


			const bool bNodeIsVisible = FSlateRect::DoRectanglesIntersect( CurWidget.Geometry.GetClippingRect(), MyClippingRect );

			if (bNodeIsVisible)
			{
				const bool bSelected = SelectionToVisualize->Contains( StaticCastSharedRef<SNodePanel::SNode>(CurWidget.Widget)->GetObjectBeingDisplayed() );

				// Handle Node renaming once the node is visible
				if( bSelected && ChildNode->IsRenamePending() )
				{
					ChildNode->ApplyRename();
				}

				// Draw the node's shadow.
				if (bDrawShadowsThisFrame || bSelected)
				{
					const FSlateBrush* ShadowBrush = ChildNode->GetShadowBrush(bSelected);
					FSlateDrawElement::MakeBox(
						OutDrawElements,
						ShadowLayerId,
						CurWidget.Geometry.ToInflatedPaintGeometry(NodeShadowSize),
						ShadowBrush,
//.........这里部分代码省略.........