jr@bbn.com (John Robinson) (03/16/89)
In article <FOX.89Mar9164818@cs.cs.columbia.edu>, fox@cs (David Fox) writes: >Can anyone write a function to split a window in two such that >the displayed text does not change? This turned out to be subtler than at first blush. But an hour or two of hacking refined it to the following. I'm gonna make this my standard ^X 2, even for fast devices! -------- ; slowsplit.el ;; Response to a challenge to build a split-window with minimum redisplay. ;; In the interests of really doing this, it may move point (the case where ;; the new modeline would cover point). Replacement for ;; split-window-vertically. ;; John Robinson, <jr@bbn.com>, 16 Mar 89 (defun split-window-quietly (&optional arg) "Split the window vertically with minimum redisplay. This window becomes the uppermost of the two, and gets ARG lines. No arg means split equally." (interactive "P") (let* ((oldpt (point)) ;where cursor started (oldstart (window-start)) ;first character in window (num-arg (and arg (prefix-numeric-value arg))) ;arg if any (above (count-lines (point-min) oldstart)) ;lines above window (curr (+ above (count-lines oldstart ;lineno of point (save-excursion (beginning-of-line) (point))))) (scroll (+ 1 above ;line below split point (or num-arg (/ (window-height) 2)))) (linect (+ 1 above (count-lines oldstart ;last point in window (save-excursion (move-to-window-line -1) (point)))))) (split-window nil num-arg) ;split the window (if (< (+ 2 curr) scroll) ;old point is in upper window (progn (other-window 1) (goto-line (min linect scroll)) ;reposition lower window (recenter 0) (other-window -1)) ;and return to upper one (goto-char oldstart) ;reposition upper window (recenter 0) (other-window 1) (goto-line scroll) ;and lower window (recenter 0) (if (/= (+ 2 curr) scroll) ;unless modeline covers old point (goto-char oldpt) ;move to point, in lower window (move-to-window-line 0))))) -------- /jr jr@bbn.com or bbn!jr C'mon big money!