README

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Advanced example showing how to control an external application from the Rerun viewer, by extending the viewer UI.

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[!NOTE] #2337: In order to spawn a web viewer with these customizations applied, you have to build the web viewer of the version yourself. This is currently not supported outside of the Rerun repository.

Overview

This example is divided into two parts:

• Viewer (src/viewer.rs): Wraps the Rerun viewer inside an eframe app.
• App (src/app.rs): The application that uses the Rerun SDK.

In the app, an additional gRPC server is opened to allow the viewer to send messages to the app. Similar to the extend_viewer_ui example, the viewer is wrapped in an eframe app, which allows us to handle the extra communication logic and define our own control UI using egui.

The communication between the viewer and the app is implemented in the comms module. It defines a simple protocol to send messages between the viewer and the app using bincode. The protocol supports basic commands that the viewer can send to the app, such as logging a Boxes3D or Point3D to an entity, or changing the radius of a set of points that is being logged.

Usage

First start the Rerun SDK app with cargo run -p custom_callback --bin custom_callback_app, and then start the extended viewer with cargo run -p custom_callback --bin custom_callback_viewer.

Relationship with Viewer callbacks

The [re_viewer] crate also exposes some baseline Viewer events through the StartupOptions.on_event field, which can exist alongside your own events from widgets added by extending the UI.