Struct WlShmPool 

pub struct WlShmPool {
    pub id: u32,
    pub client_id: u32,
    pub size: usize,
    /* private fields */
}

A shared memory pool that backs one or more buffers.

In a real Wayland compositor the pool would reference a client-provided file descriptor pointing to an mmap’d region. Here we allocate from the kernel heap as a stand-in, since user-space shared memory is not yet wired for graphics.

Fields

id: u32

Pool object ID (Wayland protocol ID)

client_id: u32

Owning client ID

size: usize

Total size in bytes

Implementations

impl WlShmPool

pub fn new(id: u32, client_id: u32, size: usize) -> Self

Create a new pool with size bytes of zeroed backing memory.

pub fn create_buffer( &mut self, offset: u32, width: u32, height: u32, stride: u32, format: PixelFormat, ) -> Result<u32, KernelError>

Create a buffer that references a region within this pool.

Arguments mirror wl_shm_pool.create_buffer: offset – byte offset into the pool width, height – dimensions in pixels stride – bytes per row format – pixel format code

pub fn get_buffer(&self, buffer_id: u32) -> Option<&WlBuffer>

Get an immutable reference to a buffer.

pub fn destroy_buffer(&mut self, buffer_id: u32) -> bool

Remove a buffer from this pool.

pub fn read_buffer_pixels(&self, buffer_id: u32) -> Option<&[u8]>

Read pixel data for a buffer from the pool backing store.

Returns a slice of the pool data corresponding to the buffer’s region.

pub fn write_buffer_pixels(&mut self, buffer_id: u32, pixels: &[u8]) -> bool

Write pixel data into the pool backing store at the buffer’s offset.

Used for testing and by kernel-side rendering that needs to fill a buffer (e.g. a cursor image).

pub fn data(&self) -> &[u8]

Get raw access to the pool’s backing memory (for direct pixel reads by the compositor).

pub fn write_data(&mut self, offset: usize, data: &[u8])

Write raw bytes into the pool at a given offset.

Used by the desktop renderer to populate background/window pixel data.

pub fn resize(&mut self, new_size: usize) -> Result<(), KernelError>

Resize the pool (wl_shm_pool.resize). Only growing is allowed.