Captured Surface Control

concepts

1. Surface Control

   Captured Surface Control lets a screen-sharing site send synthetic wheel/scroll back to the captured surface. Required for many remote-control products.

2. Wheel passthrough

   The actual VC use case: wheel on the preview tile, the DOM wheel event is translated and forwarded via controller.forwardWheel() — no synthetic buttons.

3. Zoom Coach

   Programmatic zoom of the captured tab through CaptureController. Reads supported zoom levels, reports zoomLevel, and uses the trusted increaseZoomLevel(), decreaseZoomLevel(), and resetZoomLevel() methods instead of arbitrary percentages.

4. Remote Cursor

   Remote cursor safety lab for a captured tab preview. A ghost cursor verifies normalized preview coordinates, while blocked click and keyboard simulations show why the current API forwards wheel events and controls zoom but does not expose arbitrary click or key passthrough.

why it shipped

Nearly all video-conferencing Web applications offer their users the ability to share a browser tab, a native window, or screen. Many of these applications also show the local user a “preview tile” with a video of the captured display surface. All these applications suffer from the same drawback - if the user wishes to interact with a captured tab or window, the user must first switch to that surface, taking them away from the video-conferencing application. This This presents a few issues: 1. Users are distracted by the need to jump around between the video-conferencing application and

references

• ChromeStatus entry
• Spec