window-max-delta
window-max-delta is a compiled Lisp function in `window.el
'.
(window-max-delta &optional WINDOW HORIZONTAL IGNORE TRAIL NOUP NODOWN PIXELWISE)
Return maximum number of lines by which WINDOW can be enlarged.
WINDOW must be a valid window and defaults to the selected one.
The return value is zero if WINDOW cannot be enlarged.
Optional argument HORIZONTAL non-nil means return maximum number
of columns by which WINDOW can be enlarged.
The optional argument IGNORE has the same meaning as for
`window-resizable'. Optional argument TRAIL restricts the
windows that can be enlarged. If its value is `before', only
windows to the left of or above WINDOW can be enlarged. If it is
`after', only windows to the right of or below WINDOW can be
enlarged.
Optional argument NOUP non-nil means don't go up in the window
tree but try to obtain the entire space from windows within
WINDOW's combination. Optional argument NODOWN non-nil means do
not check whether WINDOW itself (and its child windows) can be
enlarged; check only whether other windows can be shrunk
appropriately.
Optional argument PIXELWISE non-nil means return number of
pixels by which WINDOW can be enlarged.