C++ FPaintArgs::GetWindowToDesktopTransform方法代码示例

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();
}

//.........这里部分代码省略.........
			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));

				FSlateDrawElement::MakeBox(
					OutDrawElements,
					++OutMaxChildLayer,
					ScaledOutline.ToPaintGeometry(),
					FCoreStyle::Get().GetBrush(TEXT("Debug.Border")),
					MyClippingRect,
					ESlateDrawEffect::None,
					DebugTint
				);
			}

			// Draw a yellow outline around any volatile elements.
			const TArray< TSharedRef<FSlateWindowElementList::FVolatilePaint> >& VolatileElements = CachedWindowElements->GetVolatileElements();
			for ( const TSharedRef<FSlateWindowElementList::FVolatilePaint>& VolatileElement : VolatileElements )
			{
				FSlateDrawElement::MakeBox(
					OutDrawElements,
					++OutMaxChildLayer,
					VolatileElement->GetGeometry().ToPaintGeometry(),
					FCoreStyle::Get().GetBrush(TEXT("FocusRectangle")),
					MyClippingRect,
					ESlateDrawEffect::None,
					FLinearColor::Yellow
				);
			}

			// Draw a white flash for any widget that invalidated us this frame.
			for ( TWeakPtr<SWidget> Invalidator : InvalidatorWidgets )
			{
				TSharedPtr<SWidget> SafeInvalidator = Invalidator.Pin();
				if ( SafeInvalidator.IsValid() )
				{
					FWidgetPath WidgetPath;
					if ( FSlateApplication::Get().GeneratePathToWidgetUnchecked(SafeInvalidator.ToSharedRef(), WidgetPath, EVisibility::All) )
					{
						FArrangedWidget ArrangedWidget = WidgetPath.FindArrangedWidget(SafeInvalidator.ToSharedRef()).Get(FArrangedWidget::NullWidget);
						ArrangedWidget.Geometry.AppendTransform( FSlateLayoutTransform(Inverse(Args.GetWindowToDesktopTransform())) );

						FSlateDrawElement::MakeBox(
							OutDrawElements,
							++OutMaxChildLayer,
							ArrangedWidget.Geometry.ToPaintGeometry(),
							FCoreStyle::Get().GetBrush(TEXT("WhiteBrush")),
							MyClippingRect,
							ESlateDrawEffect::None,
							FLinearColor::White.CopyWithNewOpacity(0.6f)
						);
					}
				}
			}

			InvalidatorWidgets.Reset();
		}

#endif

		return OutMaxChildLayer;
	}
	else
	{
		return SCompoundWidget::OnPaint(Args, AllottedGeometry, MyClippingRect, OutDrawElements, LayerId, InWidgetStyle, bParentEnabled);
	}
}

int32 SWidget::Paint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyClippingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const
{
	INC_DWORD_STAT(STAT_SlateNumPaintedWidgets);
	SLATE_CYCLE_COUNTER_SCOPE_CUSTOM_DETAILED(SLATE_STATS_DETAIL_LEVEL_MED, GSlateOnPaint, GetType());

	// Save the current layout cache we're associated with (if any)
	LayoutCache = Args.GetLayoutCache();

	// Record if we're part of a volatility pass, this is critical for ensuring we don't report a child
	// of a volatile widget as non-volatile, causing the invalidation panel to do work that's not required.
	bInheritedVolatility = Args.IsVolatilityPass();

	// If this paint pass is to cache off our geometry, but we're a volatile widget,
	// record this widget as volatile in the draw elements so that we get our own tick/paint 
	// pass later when the layout cache draws.
	if ( Args.IsCaching() && IsVolatile() )
	{
		const int32 VolatileLayerId = LayerId + 1;
		OutDrawElements.QueueVolatilePainting(
			FSlateWindowElementList::FVolatilePaint(SharedThis(this), Args, AllottedGeometry, MyClippingRect, VolatileLayerId, InWidgetStyle, bParentEnabled));

		return VolatileLayerId;
	}

	if ( bFoldTick && bCanTick )
	{
		FGeometry TickGeometry = AllottedGeometry;
		TickGeometry.AppendTransform( FSlateLayoutTransform(Args.GetWindowToDesktopTransform()) );

		SWidget* MutableThis = const_cast<SWidget*>(this);
		MutableThis->ExecuteActiveTimers( Args.GetCurrentTime(), Args.GetDeltaTime() );
		MutableThis->Tick( TickGeometry, Args.GetCurrentTime(), Args.GetDeltaTime() );
	}

	// Record hit test geometry, but only if we're not caching.
	const FPaintArgs UpdatedArgs = Args.RecordHittestGeometry(this, AllottedGeometry, MyClippingRect);

	// Paint the geometry of this widget.
	int32 NewLayerID = OnPaint(UpdatedArgs, AllottedGeometry, MyClippingRect, OutDrawElements, LayerId, InWidgetStyle, bParentEnabled);

	// Check if we need to show the keyboard focus ring, this is only necessary if the widget could be focused.
	if ( bCanSupportFocus && SupportsKeyboardFocus() )
	{
		bool bShowUserFocus = FSlateApplicationBase::Get().ShowUserFocus(SharedThis(this));
		if (bShowUserFocus)
		{
			const FSlateBrush* BrushResource = GetFocusBrush();

			if (BrushResource != nullptr)
			{
				FSlateDrawElement::MakeBox(
					OutDrawElements,
					NewLayerID,
					AllottedGeometry.ToPaintGeometry(),
					BrushResource,
					MyClippingRect,
					ESlateDrawEffect::None,
					BrushResource->GetTint(InWidgetStyle)
					);
			}
		}
	}

	return NewLayerID;
}