Code review comment for lp://staging/~alan-griffiths/mir/client-initiates-user-move-and-resize

> How is this API to be used by the client? I.e. where is the client specifying
> the new size/position?

The client isn't specifying the position or size. It is requesting the shell treats an input event as the beginning of a gesture.

> Is it that the client gets a mouseDown event with a cookie that it decides
> should cause a resize/move, so calls the mir_window_request_user_resize with
> that cookie. Then
> (a) shell intercepts all other input events, instead sending resize events to
> the client? Or
> (b) shell keep sending the mouseMove events to the client, and client resizes
> its window/buffer as it pleases (WM can restrict those choices though)?
> On resize completion, mouseUp event finally sent to client?

(a)

> If a user wants to resize the top-left corner of a window, is that a move &
> resize? Should that be an atomic operation instead?

That's an atomic operation in those shells that currently support it. Initiating the resize through a client API shouldn't change that.

> The only reason I see that Mir's current window resize api is insufficient for
> client-size-initiated-resize is the cursor - we want the cursor to be the
> shell-themed resize image, and to remain that image even if the cursor moves
> beyond the window borders.

Hmm, I can see it will be easier to reach consensus on the USER_MOVE codepath. Maybe I should split that out?