public static PropagationPaths Build(VisualElement elem, EventBase evt)
{
PropagationPaths paths = s_Pool.Get();
var eventCategory = evt.eventCategory;
// Skip element if it has no event callbacks, default action, or default action at target
if (elem.HasEventCallbacksOrDefaultActions(eventCategory))
{
paths.targetElements.Add(elem);
}
// Go through the entire hierarchy. Don't bother checking elem.HasParentEventCallbacks because
// 1. It too goes through the entire parent hierarchy, and
// 2. It would require dirtying the parent categories when we set isCompositeRoot, so more overhead
for (var ve = elem.nextParentWithEventCallback; ve != null; ve = ve.nextParentWithEventCallback)
{
if (ve.isCompositeRoot && !evt.ignoreCompositeRoots)
{
// Callback for elem must be called at the Target phase. Skip if no callback.
if (ve.HasEventCallbacksOrDefaultActions(eventCategory))
{
paths.targetElements.Add(ve);
}
}
else if (ve.HasEventCallbacks(eventCategory))
{
if (evt.tricklesDown && ve.HasTrickleDownHandlers())
{
paths.trickleDownPath.Add(ve);
}
if (evt.bubbles && ve.HasBubbleUpHandlers())
{
paths.bubbleUpPath.Add(ve);
}
}
}
return(paths);
}
private void UpdateSubTree(VisualElement ve, bool isDisplayed, List <KeyValuePair <Rect, VisualElement> > changeEvents)
{
Rect yogaLayoutRect = new Rect(ve.yogaNode.LayoutX, ve.yogaNode.LayoutY, ve.yogaNode.LayoutWidth, ve.yogaNode.LayoutHeight);
// we encode right/bottom into width/height
Rect rawPadding = new Rect(ve.yogaNode.LayoutPaddingLeft, ve.yogaNode.LayoutPaddingLeft, ve.yogaNode.LayoutPaddingRight, ve.yogaNode.LayoutPaddingBottom);
// This is not the "real" padding rect: it may differ in size and position because the borders are ignored.
// Alone, it cannot be used to identify padding size changes, because the bottom and right values depend on the
// layout rect width/height. A change in layout rect width/height with a corresponding variation in
// right/bottom values may yield the same pseudoPaddingRect. Fortunately, the layout rect size and padding rect
// size change trigger the same code path which explains why we haven't seen any issue with this so far.
Rect yogaPseudoPaddingRect = new Rect(
rawPadding.x,
rawPadding.y,
yogaLayoutRect.width - (rawPadding.x + rawPadding.width),
yogaLayoutRect.height - (rawPadding.y + rawPadding.height));
Rect lastLayoutRect = ve.lastLayout;
Rect lastPseudoPaddingRect = ve.lastPseudoPadding;
bool wasHierarchyDisplayed = ve.isHierarchyDisplayed;
VersionChangeType changeType = 0;
// Changing the layout/padding size should trigger the following version changes:
// - Size: to update the clipping rect, when required
// - Repaint: to update the geometry inside the new rect
bool layoutSizeChanged = lastLayoutRect.size != yogaLayoutRect.size;
bool pseudoPaddingSizeChanged = lastPseudoPaddingRect.size != yogaPseudoPaddingRect.size;
if (layoutSizeChanged || pseudoPaddingSizeChanged)
{
changeType |= VersionChangeType.Size | VersionChangeType.Repaint;
}
// Changing the layout/padding position should trigger the following version change:
// - Transform: to draw the element and content at the right position
bool layoutPositionChanged = yogaLayoutRect.position != lastLayoutRect.position;
bool paddingPositionChanged = yogaPseudoPaddingRect.position != lastPseudoPaddingRect.position;
if (layoutPositionChanged || paddingPositionChanged)
{
changeType |= VersionChangeType.Transform;
}
isDisplayed &= ve.resolvedStyle.display != DisplayStyle.None;
ve.isHierarchyDisplayed = isDisplayed;
if (changeType != 0)
{
ve.IncrementVersion(changeType);
}
ve.lastLayout = yogaLayoutRect;
ve.lastPseudoPadding = yogaPseudoPaddingRect;
// ignore clean sub trees
bool hasNewLayout = ve.yogaNode.HasNewLayout;
if (hasNewLayout)
{
var childCount = ve.hierarchy.childCount;
for (int i = 0; i < childCount; ++i)
{
var child = ve.hierarchy[i];
if (child.yogaNode.HasNewLayout)
{
UpdateSubTree(child, isDisplayed, changeEvents);
}
}
}
// Only send GeometryChanged events when the layout changes
// (padding changes don't affect the element's outer geometry).
if ((layoutSizeChanged || layoutPositionChanged) && ve.HasEventCallbacksOrDefaultActions(GeometryChangedEvent.EventCategory))
{
changeEvents.Add(new KeyValuePair <Rect, VisualElement>(lastLayoutRect, ve));
}
if (hasNewLayout)
{
ve.yogaNode.MarkLayoutSeen();
}
}