void ProcessEvent(EventBase evt, [NotNull] IPanel panel)
{
Event e = evt.imguiEvent;
// Sometimes (in tests only?) we receive Used events. Protect our verification from this case.
bool imguiEventIsInitiallyUsed = e != null && e.rawType == EventType.Used;
using (new EventDispatcherGate(this))
{
evt.PreDispatch(panel);
if (!evt.stopDispatch && !evt.isPropagationStopped)
{
ApplyDispatchingStrategies(evt, panel, imguiEventIsInitiallyUsed);
}
// Last chance to build a path. Some dispatching strategies (e.g. PointerCaptureDispatchingStrategy)
// don't call PropagateEvents but still need to call ExecuteDefaultActions on composite roots.
var path = evt.path;
if (path == null && evt.bubblesOrTricklesDown && evt.leafTarget is VisualElement leafTarget)
{
path = PropagationPaths.Build(leafTarget, evt);
evt.path = path;
EventDebugger.LogPropagationPaths(evt, path);
}
if (path != null)
{
foreach (var element in path.targetElements)
{
if (element.panel == panel)
{
evt.target = element;
EventDispatchUtilities.ExecuteDefaultAction(evt);
}
}
// Reset target to leaf target
evt.target = evt.leafTarget;
}
else
{
// If no propagation path, make sure EventDispatchUtilities.ExecuteDefaultAction has a target
if (!(evt.target is VisualElement target))
{
evt.target = target = panel.visualTree;
}
if (target.panel == panel)
{
EventDispatchUtilities.ExecuteDefaultAction(evt);
}
}
m_DebuggerEventDispatchingStrategy.PostDispatch(evt, panel);
evt.PostDispatch(panel);
m_ClickDetector.ProcessEvent(evt);
Debug.Assert(imguiEventIsInitiallyUsed || evt.isPropagationStopped || e == null || e.rawType != EventType.Used, "Event is used but not stopped.");
}
}
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;
}