The device is a generic method for accessing the underlying interface with the native graphics subsystem, typically the X connection or perhaps the GL context. By exposing a cairo_device_t on a surface and its various methods we enable finer control over interoperability with external interactions of the device by applications. The use case in mind is, for example, a multi-threaded gstreamer which needs to serialise its own direct access to the device along with Cairo's across many threads. Secondly, the cairo_device_t is a unifying API for the mismash of backend specific methods for controlling creation of surfaces with explicit devices and a convenient hook for debugging and introspection. The principal components of the API are the memory management of: cairo_device_reference(), cairo_device_finish() and cairo_device_destroy(); along with a pair of routines for serialising interaction: cairo_device_acquire() and cairo_device_release() and a method to flush any outstanding accesses: cairo_device_flush(). The device for a particular surface may be retrieved using: cairo_surface_get_device(). The device returned is owned by the surface.
Showing with 406 additions and 13 deletions