Resize child windows of window PARENT vertically by DELTA lines.
PARENT must be a vertically combined internal window.
Optional argument HORIZONTAL non-nil means resize child windows of
PARENT horizontally by DELTA columns. 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 lines.
Optional argument IGNORE non-nil means ignore restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings. If IGNORE equals `safe', live
windows may get as small as `window-safe-min-height' lines and
`window-safe-min-width' columns. If IGNORE is a window, ignore
restrictions for that window only. Any other non-nil value means
ignore all of the above restrictions for all windows.
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.
Return the symbol `normalized' if new normal sizes have been
already set by this routine.