A view’s bounding box, described in the view’s own coordinate system. Concretely, |AlignedExtent| describes the minimal and maximal points of a view’s bounding box, which is rectangular and axis-aligned.
Geometric data of a view.
A view bounding box, described in another view’s coordinate system. Concretely, |RotatableExtent| describes the origin, size, and rotation angle about the origin, for a view’s bounding box.
Data for a particular view: identifier, position, and children.
A description of the context view and its descendant views, if any.
A Stream of incoming requests for ViewTreeWatcher
Response for fuchsia.ui.observation.geometry.ViewTreeWatcher.Watch.


A method of obtaining view tree snapshots for a particular view, the “context view”, and its child views, if any. The returned data is a sequence of snapshots during the period of observation, which starts at the client’s prior Watch() call’s [epoch_end] (or zx.time 0), and ending at the current [epoch_end]. The timebase is ZX_CLOCK_MONOTONIC.


The maximum number of ViewTreeSnapshots a client can expect in a Watch call’s response. The number of ViewTreeSnapshots can be less than BUFFER_SIZE when the size of a Watch call’s response exceeds the limit of a FIDL channel.
The maximum number of ViewDescriptors a client can expect in a ViewTreeSnapshot.