private void ReleaseChildList()
{
if (!ReferenceEquals(m_Owner.m_Children, s_EmptyList))
{
var children = m_Owner.m_Children;
m_Owner.m_Children = s_EmptyList;
VisualElementListPool.Release(children);
}
}
/// <summary>
/// Remove all child elements from this element's contentContainer
/// </summary>
public void Clear()
{
if (m_Owner.elementPanel != null && m_Owner.elementPanel.duringLayoutPhase)
{
throw new InvalidOperationException(k_InvalidHierarchyChangeMsg);
}
if (childCount > 0)
{
// Copy children to a temporary list because removing child elements from
// the panel may trigger modifications (DetachFromPanelEvent callback)
// of the same list while we are in the foreach loop.
var elements = VisualElementListPool.Copy(m_Owner.m_Children);
ReleaseChildList();
m_Owner.yogaNode.Clear();
if (m_Owner.requireMeasureFunction)
{
m_Owner.AssignMeasureFunction();
}
foreach (VisualElement e in elements)
{
e.InvokeHierarchyChanged(HierarchyChangeType.Remove);
e.hierarchy.SetParent(null);
e.m_LogicalParent = null;
m_Owner.elementPanel?.OnVersionChanged(e, VersionChangeType.Hierarchy);
}
if (m_Owner.imguiContainerDescendantCount > 0)
{
int totalChange = m_Owner.imguiContainerDescendantCount;
if (m_Owner.isIMGUIContainer)
{
totalChange--;
}
m_Owner.ChangeIMGUIContainerCount(-totalChange);
}
VisualElementListPool.Release(elements);
m_Owner.IncrementVersion(VersionChangeType.Hierarchy);
}
}
protected void OnMouseDown(MouseDownEvent e)
{
if (CanStartManipulation(e))
{
VisualSplitter visualSplitter = target as VisualSplitter;
FlexDirection flexDirection = visualSplitter.resolvedStyle.flexDirection;
if (m_AffectedElements != null)
{
VisualElementListPool.Release(m_AffectedElements);
}
m_AffectedElements = visualSplitter.GetAffectedVisualElements();
var shouldUseEvent = false;
for (int i = 0; i < m_AffectedElements.Count - 1; ++i)
{
VisualElement visualElement = m_AffectedElements[i];
Rect splitterRect = visualSplitter.GetSplitterRect(visualElement);
if (splitterRect.Contains(e.localMousePosition))
{
bool isReverse = flexDirection == FlexDirection.RowReverse || flexDirection == FlexDirection.ColumnReverse;
if (isReverse)
{
m_ActiveVisualElementIndex = i + 1;
m_NextVisualElementIndex = i;
}
else
{
m_ActiveVisualElementIndex = i;
m_NextVisualElementIndex = i + 1;
}
shouldUseEvent = true;
}
}
if (shouldUseEvent)
{
m_Active = true;
target.CaptureMouse();
e.StopPropagation();
e.PreventDefault();
}
}
}