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Re: scrolling very buggy (slider, arrows) under OS X
From: |
David Reitter |
Subject: |
Re: scrolling very buggy (slider, arrows) under OS X |
Date: |
Sat, 13 Mar 2004 11:34:47 +0100 |
On 12 Mar 2004, at 00:23, Miles Bader wrote:
On Thu, Mar 11, 2004 at 10:03:39PM +0000, David Reitter wrote:
Doesn't that violate the basic principle of UI design that you
shouldn't do
things that reduce 'perceived stability' of the UI?
I've never heard of such a `basic principle of UI design', but then
people
often seem to make those things up on the spot anyway.
For a discussion of 'perceived stability', I believe a good article
would be
@incollection{woods88cognitive,
AUTHOR = {David Woods and Emilie Roth},
TITLE = {Cognitive Systems Engineering},
YEAR = 1988,
BOOKTITLE = {Handbook of HumanComputer Interaction},
EDITOR = {M. Helander},
publisher = {Elsevier},
address = {North Holland},
PAGES = {1-43},
KEYWORDS = {}}
You will also find information in the writings of Jakob Nielsen
(www.useit.com) -- he has a whole lot, and certainly some things
controversial.
The user need not be aware of the reason behind every detail of
behavior.
No, not consciously aware. Behavior should be intuitively
understandable.
_Scrolling_ in emacs is typically line-based, it's just
_scrollbar-sizing_
(and other operations that display buffer-positioning, e.g., the
mode-line
percentage display) that is character-based.
Well, then either the scrolling or the scrollbar-sizing is inconsistent
behavior.
Line-based scrollbar sizing would be _really hard_ in emacs, because
although
it knows the number of displayed lines, emacs has _no idea_ how many
lines
are in the buffer (much less their `displayed size'), and calculating
it is
computationally very expensive.
IMHO this seems to be the real problem.
However, given that the scrollbar / slider size give an intuitive guess
of the size of the document, wouldn't it suffice to calculate how many
average lines fit into the window, and how many lines a document has?
And then, unless the number of lines or the size of the window changes,
this wouldn't have to be updated?
I mean, most editors I know do this, even editors that come as UI
widgets (such as the one I am using right now to compose this message),
so calculating the slider size doesn't have to be computationally
expensive.