Surface Update Component

The Surface Update component provides a communication mechanism between the composition engine and its clients.

Target audience: Device creators.

The CBR package name for the Surface Update component is graphics_surfaceupdate.

• Surface Update Component Overview
  Each graphics composition surface has at least two interested stakeholders: the process responsible for drawing and maintaining the content and the composition engine, which uses the surface for creating the display. When one of the stakeholders does something to the surface, it usually means that another stakeholder needs to do something too. The Surface Update component provides a channel for the stakeholders to inform each other of changes.
• Global Surface Updates
  Global surface updates are surface composition update commands that are submitted to all displays rather than to a single one. This causes the Surface Update Server to broadcast the update to all of the registered composition engine instances. Each of these then determines whether the surface is displayed on its associated screen and if so, forces an update.