window--resizable

window--resizable is a compiled Lisp function in `window.el'.

(window--resizable WINDOW DELTA &optional HORIZONTAL IGNORE TRAIL NOUP NODOWN PIXELWISE)

Return DELTA if WINDOW can be resized vertically by DELTA lines.
WINDOW must be a valid window and defaults to the selected one.
Optional argument HORIZONTAL non-nil means return DELTA if WINDOW
can be resized horizontally by DELTA columns. A return value of
zero means that WINDOW is not resizable.

DELTA positive means WINDOW shall be enlarged by DELTA lines or
columns. If WINDOW cannot be enlarged by DELTA lines or columns,
return the maximum value in the range 0..DELTA by which WINDOW
can be enlarged.

DELTA negative means WINDOW shall be shrunk by -DELTA lines or
columns. If WINDOW cannot be shrunk by -DELTA lines or columns,
return the minimum value in the range DELTA..0 that can be used
for shrinking WINDOW.

The optional argument IGNORE has the same meaning as for
`window-resizable'. Optional argument TRAIL `before' means only
windows to the left of or below WINDOW can be shrunk. Optional
argument TRAIL `after' means only windows to the right of or
above WINDOW can be shrunk.

Optional argument NOUP non-nil means don't go up in the window
tree but check only whether space can be obtained from (or given
to) WINDOW's siblings. Optional argument NODOWN non-nil means
don't go down in the window tree. This means do not check
whether resizing would violate size restrictions of WINDOW or its
child windows.

Optional argument PIXELWISE non-nil means interpret DELTA as
number of pixels.