Struct wayland_server::protocol::wl_subsurface::WlSubsurface

pub struct WlSubsurface { /* private fields */ }

sub-surface interface to a wl_surface

An additional interface to a wl_surface object, which has been made a sub-surface. A sub-surface has one parent surface. A sub-surface’s size and position are not limited to that of the parent. Particularly, a sub-surface is not automatically clipped to its parent’s area.

A sub-surface becomes mapped, when a non-NULL wl_buffer is applied and the parent surface is mapped. The order of which one happens first is irrelevant. A sub-surface is hidden if the parent becomes hidden, or if a NULL wl_buffer is applied. These rules apply recursively through the tree of surfaces.

The behaviour of a wl_surface.commit request on a sub-surface depends on the sub-surface’s mode. The possible modes are synchronized and desynchronized, see methods wl_subsurface.set_sync and wl_subsurface.set_desync. Synchronized mode caches the wl_surface state to be applied when the parent’s state gets applied, and desynchronized mode applies the pending wl_surface state directly. A sub-surface is initially in the synchronized mode.

Sub-surfaces also have another kind of state, which is managed by wl_subsurface requests, as opposed to wl_surface requests. This state includes the sub-surface position relative to the parent surface (wl_subsurface.set_position), and the stacking order of the parent and its sub-surfaces (wl_subsurface.place_above and .place_below). This state is applied when the parent surface’s wl_surface state is applied, regardless of the sub-surface’s mode. As the exception, set_sync and set_desync are effective immediately.

The main surface can be thought to be always in desynchronized mode, since it does not have a parent in the sub-surfaces sense.

Even if a sub-surface is in desynchronized mode, it will behave as in synchronized mode, if its parent surface behaves as in synchronized mode. This rule is applied recursively throughout the tree of surfaces. This means, that one can set a sub-surface into synchronized mode, and then assume that all its child and grand-child sub-surfaces are synchronized, too, without explicitly setting them.

If the wl_surface associated with the wl_subsurface is destroyed, the wl_subsurface object becomes inert. Note, that destroying either object takes effect immediately. If you need to synchronize the removal of a sub-surface to the parent surface update, unmap the sub-surface first by attaching a NULL wl_buffer, update parent, and then destroy the sub-surface.

If the parent wl_surface object is destroyed, the sub-surface is unmapped.

See also the Request enum for this interface.

Trait Implementations

impl Clone for WlSubsurface

fn clone(&self) -> WlSubsurface

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WlSubsurface

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq<WlSubsurface> for WlSubsurface

fn eq(&self, other: &WlSubsurface) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl Resource for WlSubsurface

type Request = Request

type Event = Event

fn interface() -> &'static Interface

fn id(&self) -> ObjectId

fn version(&self) -> u32

fn data<U: 'static>(&self) -> Option<&U>

fn object_data(&self) -> Option<&Arc<dyn Any + Send + Sync>>

fn handle(&self) -> &WeakHandle

fn from_id(conn: &DisplayHandle, id: ObjectId) -> Result<Self, InvalidId>

fn send_event(&self, evt: Self::Event) -> Result<(), InvalidId>

fn parse_request(
    conn: &DisplayHandle,
    msg: Message<ObjectId>
) -> Result<(Self, Self::Request), DispatchError>

fn write_event(
    &self,
    conn: &DisplayHandle,
    msg: Self::Event
) -> Result<Message<ObjectId>, InvalidId>

fn post_error(
    &self,
    dh: &DisplayHandle,
    code: impl Into<u32>,
    error: impl Into<String>
)

impl Eq for WlSubsurface