private static void HandleEventAcrossPropagationPath(EventBase evt)
{
// Build and store propagation path
var leafTarget = (VisualElement)evt.leafTarget;
var path = PropagationPaths.Build(leafTarget, evt);
evt.path = path;
EventDebugger.LogPropagationPaths(evt, path);
var panel = leafTarget.panel;
// Phase 1: TrickleDown phase
// Propagate event from root to target.parent
if (evt.tricklesDown)
{
evt.propagationPhase = PropagationPhase.TrickleDown;
for (int i = path.trickleDownPath.Count - 1; i >= 0; i--)
{
if (evt.isPropagationStopped)
{
break;
}
var element = path.trickleDownPath[i];
if (evt.Skip(element) || element.panel != panel)
{
continue;
}
evt.currentTarget = element;
evt.currentTarget.HandleEvent(evt);
}
}
// Phase 2: Target / DefaultActionAtTarget
// Propagate event from target parent up to root for the target phase
// Call HandleEvent() even if propagation is stopped, for the default actions at target.
evt.propagationPhase = PropagationPhase.AtTarget;
foreach (var element in path.targetElements)
{
if (evt.Skip(element) || element.panel != panel)
{
continue;
}
evt.target = element;
evt.currentTarget = evt.target;
evt.currentTarget.HandleEvent(evt);
}
// Call ExecuteDefaultActionAtTarget
evt.propagationPhase = PropagationPhase.DefaultActionAtTarget;
foreach (var element in path.targetElements)
{
if (evt.Skip(element) || element.panel != panel)
{
continue;
}
evt.target = element;
evt.currentTarget = evt.target;
evt.currentTarget.HandleEvent(evt);
}
// Reset target to original target
evt.target = evt.leafTarget;
// Phase 3: bubble up phase
// Propagate event from target parent up to root
if (evt.bubbles)
{
evt.propagationPhase = PropagationPhase.BubbleUp;
foreach (var element in path.bubbleUpPath)
{
if (evt.Skip(element) || element.panel != panel)
{
continue;
}
evt.currentTarget = element;
evt.currentTarget.HandleEvent(evt);
}
}
evt.propagationPhase = PropagationPhase.None;
evt.currentTarget = null;
}
