Trait cros_libva::PictureState
source · pub trait PictureState: Sealed { }Expand description
A Picture will only have valid YUV data after a sequence of operations are performed in a
particular order. This order correspond to the following VA-API calls: vaBeginPicture,
vaRenderPicture, vaEndPicture and vaSyncSurface. This trait enforces this ordering by
implementing the Typestate pattern to constrain what operations are available in what particular
states.
The states for the state machine are:
- PictureNew -> PictureBegin
- PictureBegin -> PictureRender
- PictureRender ->PictureEnd
- PictureEnd -> PictureSync
Where the surface can be reclaimed in both PictureNew and PictureSync, as either no
operation took place (as in PictureNew), or it is guaranteed that the operation has already
completed (as in PictureSync).
More information about the Typestate pattern can be found at http://cliffle.com/blog/rust-typestate/