bool TryToPickInCanvas(Vector2 mousePosition)
{
if (viewport == null)
{
return(false);
}
var localMouse = m_Canvas.WorldToLocal(mousePosition);
if (!m_Canvas.ContainsPoint(localMouse))
{
m_ParentTracker?.Deactivate();
m_PlacementIndicator?.Deactivate();
return(false);
}
var pickedElement = Panel.PickAllWithoutValidatingLayout(m_Canvas, mousePosition);
// Don't allow selection of elements inside template instances or outside current active document.
pickedElement = pickedElement.GetClosestElementPartOfCurrentDocument();
if (pickedElement != null && !pickedElement.IsPartOfActiveVisualTreeAsset(m_PaneWindow.document))
{
pickedElement = null;
}
// Get Closest valid element.
pickedElement = pickedElement.GetClosestElementThatIsValid(IsPickedElementValid);
if (pickedElement == null)
{
m_ParentTracker?.Deactivate();
m_PlacementIndicator?.Deactivate();
m_LastHoverElement = null;
return(false);
}
// The placement indicator might decide to change the parent.
if (SupportsPlacementIndicator() && m_PlacementIndicator != null)
{
m_PlacementIndicator.Activate(pickedElement, mousePosition);
pickedElement = m_PlacementIndicator.parentElement;
}
m_ParentTracker.Activate(pickedElement);
m_LastHoverElement = pickedElement;
if (SupportsPlacementIndicator() && m_PlacementIndicator != null)
{
m_LastHoverElementChildIndex = m_PlacementIndicator.indexWithinParent;
}
return(true);
}
void PerformDragInner(VisualElement target, Vector2 mousePosition)
{
// Move dragged element.
m_DraggedElement.style.left = mousePosition.x;
m_DraggedElement.style.top = mousePosition.y;
m_LastRowHoverElement?.RemoveFromClassList(s_TreeItemHoverHoverClassName);
m_LastRowHoverElement?.Query(className: BuilderConstants.ExplorerItemReorderZoneClassName).ForEach(e => e.RemoveFromClassList(s_TreeItemHoverWithDragBetweenElementsSupportClassName));
// Note: It's important for the Hierarchy/Stylesheet panes to be checked first because
// this check does not account for which element is on top of which other element
// so if the Viewport is panned such that the Canvas is behind the Hierarchy,
// the TryToPickIn..() call will return true for the Canvas.
var isCanvasBlocked = CanPickInExplorerRoot(mousePosition, builderHierarchyRoot) || CanPickInExplorerRoot(mousePosition, builderStylesheetRoot);
if (isCanvasBlocked)
{
var validHover = TryToPickInExplorer(mousePosition, builderHierarchyRoot) || TryToPickInExplorer(mousePosition, builderStylesheetRoot);
if (validHover)
{
VisualElement pickedElement;
int index;
GetPickedElementFromHoverElement(out pickedElement, out index);
if (pickedElement == null)
{
return;
}
// Mirror final drag destination in the viewport using the placement indicator.
m_PlacementIndicator?.Activate(pickedElement, index);
m_Active = true;
PerformDrag(target, pickedElement, index);
return;
}
}
else
{
var validHover = TryToPickInCanvas(mousePosition);
if (validHover)
{
m_Active = true;
PerformDrag(target, m_LastHoverElement, m_LastHoverElementChildIndex);
return;
}
}
m_PlacementIndicator?.Deactivate();
PerformDrag(target, null);
}
