componentsAtLocation<T> method
This is a generic implementation of componentsAtPoint; refer to those docs for context.
This will find components intersecting a given location context T
. The
context can be a single point or a more complicated structure. How to
interpret the structure T is determined by the provided lambdas,
transformContext
and checkContains
.
A simple choice of T would be a simple point (i.e. Vector2). In that case
transformContext needs to be able to transform a Vector2 on the parent
coordinate space into the coordinate space of a provided
CoordinateTransform; and checkContains
must be able to determine if
a given Component "contains" the Vector2 (the definition of "contains"
will vary and shall be determined by the nature of the chosen location
context T
).
Implementation
Iterable<Component> componentsAtLocation<T>(
T locationContext,
List<T>? nestedContexts,
T? Function(CoordinateTransform, T) transformContext,
bool Function(Component, T) checkContains,
) sync* {
nestedContexts?.add(locationContext);
if (_children != null) {
for (final child in _children!.reversed()) {
if (child is IgnoreEvents && child.ignoreEvents) {
continue;
}
T? childPoint = locationContext;
if (child is CoordinateTransform) {
childPoint = transformContext(
child as CoordinateTransform,
locationContext,
);
}
if (childPoint != null) {
yield* child.componentsAtLocation(
childPoint,
nestedContexts,
transformContext,
checkContains,
);
}
}
}
final shouldIgnoreEvents =
this is IgnoreEvents && (this as IgnoreEvents).ignoreEvents;
if (checkContains(this, locationContext) && !shouldIgnoreEvents) {
yield this;
}
nestedContexts?.removeLast();
}