docs/development/debugging/ui_tips.md

# UI debugging tips

For general debugging info see the
[Fuchsia Debugging Workflow](/docs/development/debugging/debugging.md).

## Capture the Screen

### Take a Screenshot

A screenshot takes a screenshot of what is currently displayed on the Fuchsia
device's screen. It returns a 2D buffer.

From the Fuchsia device console, run:

```posix-terminal
screencap /tmp/filename.ppm
```

From your host workstation, run:

```posix-terminal
fx scp [$(fx get-device-addr)]:/tmp/filename.ppm /tmp/filename.ppm
```

### Take a Scenic Snapshot

A Scenic snapshot takes a 3D representation of what is currently displayed on
the screen. It usually takes longer to capture than a screenshot, and can be
used to visualize issues with layout of 3D content.

From your host workstation, run:

```posix-terminal
fx shell gltf_export > filename.gltf
```

You can upload `filename.gltf` to any gltf viewer, such as this
[online viewer](https://gltf-viewer.donmccurdy.com/).

### Dump the SceneGraph as Text

The [SceneGraph](/docs/concepts/graphics/scenic/scenic.md#scenic-resource-graph)
as text is useful when you want to see all the resources, including non-visible
elements such as transform matrices.

#### Dump the SceneGraph in Fuchsia snapshot

A Fuchsia snapshot contains the SceneGraph that is rendered to the screen.
Capture it from your host workstation using the following commands:

```posix-terminal
fx snapshot
```

```posix-terminal
unzip <snapshot output file>
```

Then, look for Scenic’s info in the inspect file:

```posix-terminal
less inspect.json
```

#### Dump the SceneGraph and all Scenic resources

To capture all the resources created, including those that are not currently
attached to the main SceneGraph, you can use `dump-scenes`. From your host
workstation, run the following command:

```posix-terminal
fx shell "cat /hub/c/scenic.cmx/*/out/debug/dump-scenes"
```