🚀 go-pugleaf

In article <1992Nov12.222638.2886@nas.nasa.gov> lonhyn@gulag.nas.nasa.gov (Lonhyn T. Jasinskyj) writes:


   VERSION:  Epoch 4.2, but the same held for Epoch 4.x, not sure about 3.x

   on an SGI Iris running Irix 4.0.x (not really important, I think
   this should happen on any architecture)


   The problem we are having here is that when you scroll-down
   (i.e. M-v) the following happens:

	In Emacs:
	 - move back by one "height of window" (height) number of lines
	 - the cursor is left at the last visible line in the window
	 - can continue this until you are at the beginning at which time
	   your cursor is on line height (or height minus one)
	   AND the first line in the file is at the top of the window

	In Epoch:
	 - move back by one "height of window" (height) number of lines
	 - the cursor is left at the last visible line in the window
	 - the function layout_window() then RECENTERS that line to the
	   middle of the window.
	 - continue this scrolling by height lines until you are at the
	   beginning at which point your cursor is on line "height"
	   BUT that line has now been recentered leaving the first
	   height/2 lines perpetually unreachable using scroll-down



I just experienced a very similar problem on my Sun Sparc, so the
problem doesn't rest in the Iris.  The problem doesn't happen in all
my epoch incarnations, only in this one "application" that I've built
on top of epoch.  By application, I mean a great big bunch of elisp
code.

I get the undesired recentering of the window as I scroll with
(scroll-down 1).  In the application that has the problem, I can
easily produce the effect by binding that to a key such as
(local-set-key "\M-n" '(func () (scroll-down 1)) and invoking [M-n]
when the cursor is on the bottom line of the window.  You have to be
partway through a file that is bigger than the window, of course.


OK, I've now tracked down the problem in my application.  Scroll-down
breaks when I have fonts of two different sizes on the mode line!
My app highlights the file name in the mode line using modeline
styles, and I only have this problem when I mix fonts on the modeline.

This may not be the real true and only problem, but it solved my
problem and sure is a big hint!





--
B<   Brian Kahn   blk@mitre.org   "may the farce be with you"