Let's build a functional "viewerframe mode refresh top" widget from scratch. We will use vanilla JavaScript for clarity.

Accessing cameras this way can have real-world consequences:

You are scrolling through a high-frequency financial chart (viewerframe) at 120fps. The bottom half of the chart shows data from 10 seconds ago, while the top half shows live data. This "tearing" occurs because the GPU buffer flipped mid-scan.

Describing a bug fix or new feature.