Display Driver Component

The Display Driver component (also known as the Display Channel Driver) is new in Symbian^3 and is for use in ScreenPlay only. The Display Driver component includes a reference implementation, which a composition implementation can use to display the composited output on the screen without tearing. However, the use of the Display Channel Driver is optional. Implementers of the Composition Interface are not required to use it.

The Display Channel Driver provides the RDisplayChannel API. This provides methods that post double-buffered composition frame buffers to the screen and set and get the screen rotation, resolution and other display properties. RDisplayChannel also allows composition surfaces to be posted directly to the screen without being composited with other layers. This is referred to as fast path mode and is typically used when a video or game occupies the whole screen. The RDisplayChannel API uses the term user buffers for surfaces that are in fast path mode.

Note: The Display Channel Driver does not replace the existing LCD Driver, which is implemented as a standard kernel extension and is therefore also known as the LCD Extension. This continues to be required and provides support for legacy applications.

• Implementing Dynamic DSA Allocation
  This topic describes how device creators can allocate the Direct Screen Access (DSA) buffer dynamically. This feature is new in Symbian^3 (S^3).