window--resize-this-window

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

(window--resize-this-window WINDOW DELTA &optional HORIZONTAL IGNORE ADD TRAIL EDGE CHAR-SIZE)

Resize WINDOW vertically by DELTA pixels.
Optional argument HORIZONTAL non-nil means resize WINDOW
horizontally by DELTA pixels.

The optional argument IGNORE has the same meaning as for
`window-resizable'. Optional argument ADD non-nil means add
DELTA to the new total size of WINDOW.

Optional arguments TRAIL and EDGE, when non-nil, refine the set
of windows that shall be resized. If TRAIL equals `before',
resize only windows on the left or above EDGE. If TRAIL equals
`after', resize only windows on the right or below EDGE. Also,
preferably only resize windows adjacent to EDGE.

If the optional argument CHAR-SIZE is a positive integer, it specifies
the number of pixels by which windows are incrementally resized.
If CHAR-SIZE is nil, this means to use the value of
`frame-char-height' or `frame-char-width' of WINDOW's frame.

This function recursively resizes WINDOW's child windows to fit the
new size. Make sure that WINDOW is `window--resizable' before
calling this function. Note that this function does not resize
siblings of WINDOW or WINDOW's parent window. You have to
eventually call `window-resize-apply' in order to make resizing
actually take effect.