wp_fifo_v1¤
Fifo interface
A fifo object for a surface that may be used to add display refresh constraints to content updates.
Methods:
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set_barrier–Sets the start point for a fifo constraint
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wait_barrier–Adds a fifo constraint to a content update
-
destroy–Destroy the fifo interface
Fatal error
These fatal protocol errors may be emitted in response to illegal requests.
-
surface_destroyed–The associated surface no longer exists
set_barrier() -> None
Sets the start point for a fifo constraint
When the content update containing the "set_barrier" is applied, it sets a "fifo_barrier" condition on the surface associated with the fifo object. The condition is cleared immediately after the following latching deadline for non-tearing presentation.
The compositor may clear the condition early if it must do so to ensure client forward progress assumptions.
To wait for this condition to clear, use the "wait_barrier" request.
"set_barrier" is double-buffered state, see wl_surface.commit.
Requesting set_barrier after the fifo object's surface is destroyed will generate a "surface_destroyed" error.
wait_barrier() -> None
Adds a fifo constraint to a content update
Indicate that this content update is not ready while a "fifo_barrier" condition is present on the surface.
This means that when the content update containing "set_barrier" was made active at a latching deadline, it will be active for at least one refresh cycle. A content update which is allowed to tear might become active after a latching deadline if no content update became active at the deadline.
The constraint must be ignored if the surface is a subsurface in synchronized mode. If the surface is not being updated by the compositor (off-screen, occluded) the compositor may ignore the constraint. Clients must use an additional mechanism such as frame callbacks or timestamps to ensure throttling occurs under all conditions.
"wait_barrier" is double-buffered state, see wl_surface.commit.
Requesting "wait_barrier" after the fifo object's surface is destroyed will generate a "surface_destroyed" error.
destroy() -> None
Destroy the fifo interface
Informs the server that the client will no longer be using this protocol object.
Surface state changes previously made by this protocol are unaffected by this object's destruction.