| // Copyright 2018 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| library fuchsia.ui.app; |
| |
| using fuchsia.sys; |
| |
| /// ViewProvider is the standard mechanism for two modules to each obtain half |
| /// of a shared eventpair token. The shared token is a capability allowing the |
| /// modules to ask Scenic to create a ViewHolder/View pair. The resulting |
| /// View and ViewHolder are linked together until either one is destroyed. |
| /// |
| /// Modules are free to use any other mechanism to agree upon the shared |
| /// eventpair token, and use this to create the linked ViewHolder/View. |
| /// ViewProvider is given for the convenience of clients that don't require |
| /// a more complex implementation. |
| [Discoverable] |
| protocol ViewProvider { |
| /// Creates a new View under the control of the ViewProvider. |
| /// |
| /// `token` is one half of the shared eventpair which will bind the new View |
| /// to its associated ViewHolder. The ViewProvider will use `token` to |
| /// create its internal View representation. The caller is expected to use |
| /// its half to create corresponding ViewHolder object. |
| /// |
| /// `incoming_services` allows clients to request services from the |
| /// ViewProvider implementation. `outgoing_services` allows clients to |
| /// provide services of their own to the ViewProvider implementation. |
| /// |
| /// Clients can embed a ViewHolder (and by proxy the paired View) into their |
| /// scene graph by using `Node.AddChild()`. The ViewHolder cannot itself |
| /// have any children. A ViewProvider implementation can nest scene objects |
| /// within its View by using `View.AddChild()`. The View itself |
| /// cannot be a child of anything. |
| /// |
| /// Modules can use these mechanisms to establish a distributed, |
| /// inter-process scene graph. |
| CreateView(handle<eventpair> token, |
| request<fuchsia.sys.ServiceProvider>? incoming_services, |
| fuchsia.sys.ServiceProvider? outgoing_services); |
| }; |