scrolling

Scrolling It's an integral part of just about any graphical user interface,
including emacs. However, I always found that the default way scrolling works
in emacs left something to be desired. It puts the scroll bar on the left (!),
and when scrolling around, it does not scroll smoothly, but instead it seem to
do so in bursts. But, this being emacs, we can change it!

First, the position of the scroll bar. Presumably for historical reasons,
emacs puts the scroll bar on the left of the window, unlike most other
programs. We can easily change that, by putting the following in .emacs
(or ~/.emacs.d/init.el):

(set-scroll-bar-mode 'right)

Instead of right, you can also use left, or nil to hide the scroll bar
completely. You can also do this through the menu (Options / Show/Hide /
Scroll bar). Note that on X, when the cursor (point) reaches the end of the
document, the slider on the scroll bar may not be at the bottom; I understand
this is because of some disagreement between Emacs and the toolkit (GTK+ in
this case).

Now, what about the other issue, the non-smoothness when scrolling with the
cursor-keys or with C-n, C-p? Below are my settings for making scrolling a
bit smoother, and the explanation. Of course, these are just my personal
preferences.

(setq
  scroll-margin 0                  
  scroll-conservatively 100000
  scroll-preserve-screen-position 1)

• 
  The scroll-margin. This determines when scrolling should start; by
  setting it to 0, emacs will start to scroll whenever you are entering the
  top or bottom line of the window. You can also this to, say, 5 to let
  scrolling start whenever you're getting closer than 5 lines from top or bottom
  
  


• 
  Then, scroll-conservatively determines how far the cursor is allowed to
  be distanced from the center of the screen when scrolling start. The
  default sets this to 0, which means that whenever you start scrolling, the
  cursor jumps to the center of the screen. I find that quite annoying, so I
  set it to some big number (the 'effective maximum' for that is
  lines-in-window / 2, but you can put any bigger number there to avoid the
  jumpiness)
  


• 
  scroll-preserve-screen-position tries to maintain the current screen
  position when you scroll using Page-Up/Page-Down. I like that.
  
  

There are also the variables scroll-up-aggressively and

scroll-down-aggressively. Normally, they determine how far emacs will scroll
(up and down, respectively) when it does so. However, they don't make any
difference with a big scroll-conservatively like I am using. Still, if you
want to play with it, their values are fractions between 0.0 and 1.0
(inclusive); a value of 1 means that it will move a full screen when scrolling
starts, a value of 0.0 causes a move of only one single line.