Code review comment for lp:~kdub/mir/RFC-surface-arrangements

54 +/** Specify the position of the stream within the surface. This establishes
55 + * positions relative to the other streams in the surface, and is not a
56 + * guarantee of the final composited ons

You appear to have garbled a comment here ☺. I'm not sure if what the comment says is right; we *should* be able to say that the relative position is guaranteed to be correct, but we guarantee nothing about the position of (0,0) onscreen.

This does raise the question of whether or not we want to clip streams to the parent surface; Wayland doesn't for subsurfaces, and I think GTK uses this for tooltips and such. That said, we know how to position tooltips and such better than the toolkit, so they shouldn't really be using it for this purpose.

I don't know if we should clip to the parent window or not; whichever way we go, we should document and test it, though.

This otherwise looks like sensible API to me. I do think we'll need at least an optional synchronise-on-swap_buffers mode, though.