Not a real bug: vertical scrolling with variable height fonts.

[Lute Kamstra]

Dear People,

This is more of a feature request than a bug report.  It concerns
vertical scrolling using GNU Emacs 21 new redisplay engine.


In GNU Emacs 20, all the lines in a frame were of equal height and a
frame's size was measured in terms lines.  As a result, a line was
either visible or it was not.  If you moved the point past the last
visible line, the frame would be redisplayed and you could find your
cursor somewhere in the middle of the window.

In GNU Emacs 21, lines can have different heights.  It can therefore
happen that only the upper part of the last line is visible.  If you
move the point into such a last line, the frame is redisplayed, but
only to show the last line in its entirely.  This behavior is
confusing for me.  When the frame is redisplayed, I automatically look
for the point in the middle of the window and in this case the point
is still on the last line.  Moving the point further down causes
another redisplay that does leave the point in the middle of the
window.

I would prefer the following behavior.  If the point moves into a last
line that is partly visible, let the triggered redisplay position that
line in the middle of the window (instead of on the bottom of the
window).  I find this behavior more consistent.

Could you implement my proposal an introduce a option that lets the
user choose between the current behavior and my preferred behavior?

Regards,

  Lute Kamstra.

-- 
Lute Kamstra
CWI  department PNA4