Struct ReadbackSlot 

pub(crate) struct ReadbackSlot {
    pub(crate) id: u32,
    pub(crate) size: usize,
    ptr: usize,
    mapped: Mutex<bool>,
}

A pixel-pack buffer the compositor’s GL readback lands in, mapped persistently so the screenshot’s caller copies the pixels out on its own thread. The mapping is valid while mapped is set; the compositor clears it, under the lock a copy holds, before it deletes the buffer or its GL context goes away.

Fields

id: u32

size: usize

ptr: usize

mapped: Mutex<bool>

Implementations

impl ReadbackSlot

pub(crate) unsafe fn new(id: u32, ptr: *const u8, size: usize) -> Self

Safety

ptr must address size readable bytes until ReadbackSlot::unmap returns.

pub(crate) fn in_use(self: &Arc<Self>) -> bool

Whether a screenshot still holds the slot, which the compositor then neither reuses nor deletes.

pub(crate) fn unmap(&self)

Forget the mapping, waiting out a copy under way.

pub(crate) fn copy_out(&self, len: usize) -> Result<ScreenshotBuffer, String>