window--resize-child-windows
window--resize-child-windows is a compiled Lisp function in `window.el
'.
(window--resize-child-windows PARENT DELTA &optional HORIZONTAL WINDOW IGNORE TRAIL EDGE CHAR-SIZE)
Resize child windows of window PARENT vertically by DELTA pixels.
PARENT must be a vertically combined internal window.
Optional argument HORIZONTAL non-nil means resize child windows
of PARENT horizontally by DELTA pixels. In this case PARENT must
be a horizontally combined internal window.
WINDOW, if specified, must denote a child window of PARENT that
is resized by DELTA pixels.
The optional argument IGNORE has the same meaning as for
`window-resizable'.
Optional arguments TRAIL and EDGE, when non-nil, restrict 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.
Return the symbol `normalized' if new normal sizes have been
already set by this routine.