> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://fastpix.com/docs/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://fastpix.com/docs/_mcp/server.

# Add seek preview thumbnails

> Learn how to show spritesheet-based thumbnail previews while scrubbing the seek bar in the FastPix iOS Player.

Learn how to show spritesheet-based thumbnail previews while scrubbing the seek bar in the FastPix iOS Player.

The FastPix iOS Player supports spritesheet-based thumbnail previews that appear when a user scrubs through the seek bar. If a thumbnail isn't available, the SDK falls back to showing a timestamp.

## Enable spritesheet preview

```swift
let previewConfig = FastPixSeekPreviewConfig()

playerViewController.loadSpritesheet(
    url: nil,
    previewEnable: true,
    config: previewConfig
)

playerViewController.setFallbackMode(.timestamp)
```

## Get the preview during scrubbing

Retrieve the thumbnail for a given time and pass it to the seek bar:

```swift
let result = playerViewController.fastpixThumbnailForPreview(at: time)

seekBar.updatePreviewThumbnail(
    result.image,
    time: time,
    useTimestamp: result.useTimestamp
)
```

## Secured content support

Spritesheet previews work with both private (token-protected) and DRM-protected (FairPlay) streams. The SDK handles secure fetching and rendering of spritesheet assets without exposing protected URLs.

> **Note:** The SDK automatically falls back to timestamp display if a thumbnail isn't available for the current position. Spritesheet previews work with playlists and custom seek bars.