FPopupPlacement(const FGeometry& AllottedGeometry, const FVector2D& PopupDesiredSize, EMenuPlacement PlacementMode)
{
// Compute the popup size, offset, and anchor rect in local space
LocalPopupSize = (PlacementMode == MenuPlacement_ComboBox || PlacementMode == MenuPlacement_ComboBoxRight)
? FVector2D(FMath::Max(AllottedGeometry.Size.X, PopupDesiredSize.X), PopupDesiredSize.Y)
: PopupDesiredSize;
LocalPopupOffset = GetMenuOffsetForPlacement(AllottedGeometry, PlacementMode, LocalPopupSize);
AnchorLocalSpace = FSlateRect::FromPointAndExtent(FVector2D::ZeroVector, AllottedGeometry.Size);
Orientation = (PlacementMode == MenuPlacement_MenuRight || PlacementMode == MenuPlacement_MenuLeft) ? Orient_Horizontal : Orient_Vertical;
}
FGeometry SMenuAnchor::ComputeMenuPlacement( const FGeometry& AllottedGeometry, const FVector2D& PopupDesiredSize, EMenuPlacement PlacementMode )
{
// Compute the popup size, offset, and anchor rect in local space
const FVector2D PopupSizeLocalSpace = (PlacementMode == MenuPlacement_ComboBox || PlacementMode == MenuPlacement_ComboBoxRight)
? FVector2D( FMath::Max( AllottedGeometry.Size.X, PopupDesiredSize.X ), PopupDesiredSize.Y )
: PopupDesiredSize;
const FVector2D OffsetLocalSpace = GetMenuOffsetForPlacement(AllottedGeometry, PlacementMode, PopupSizeLocalSpace);
const FSlateRect AnchorLocalSpace = FSlateRect::FromPointAndExtent(OffsetLocalSpace, AllottedGeometry.Size);
const EOrientation Orientation = (PlacementMode == MenuPlacement_MenuRight || PlacementMode == MenuPlacement_MenuLeft) ? Orient_Horizontal : Orient_Vertical;
// ask the application to compute the proper desktop offset for the anchor. This requires the offsets to be in desktop space.
const FVector2D NewPositionDesktopSpace = FSlateApplication::Get().CalculatePopupWindowPosition(
TransformRect(AllottedGeometry.GetAccumulatedLayoutTransform(), AnchorLocalSpace),
TransformVector(AllottedGeometry.GetAccumulatedLayoutTransform(), PopupSizeLocalSpace),
Orientation );
// transform the desktop offset into local space and use that as the layout transform for the child content.
return AllottedGeometry.MakeChild(
PopupSizeLocalSpace,
FSlateLayoutTransform(TransformPoint(Inverse(AllottedGeometry.GetAccumulatedLayoutTransform()), NewPositionDesktopSpace)));
}
