[Fwd: Re: scroll bar and drop down list usability]

[Johan Hanson <johan obsession se>]

Ken Fox wrote:
> 
> "Guillermo S. Romero / Familia Romero" wrote:
> > >It increasingly strikes me that scroll bars should be located on the left
> > >side of windows rather than the right.

Excuse me for being efficient and commenting on two posts at once here. =)

The GTKstep theme engine lets you put the scrollbar on the left.
You just need to theme at least one widget with the theme engine to tell
GTK to load and execute the code that patches the scrollbar code.
(actually, the patch is applied to the GtkScrolledWindow class)
Be careful with switching/browsing themes though, as GTKstep does not clean up
very well.
Your applications can crash when the theme is unloaded from the theme selector.

> For many things we don't need scrollbars at all -- the display space itself
> can be used for scrolling/panning. Just click on the space and drag. This
> solves two problems: 1) the focus of attention and scrolling area are the
> same, and 2) the scrolling area is easy to hit (Fitt's law).
> For keyboard scrolling, I think a spring-loaded mode (hold control key or something)
> combined with arrows should be standard bindings for anything that uses a
> scrollbar.

Good idea, but I think the same qualifier key should be required for both the
keyboard and mouse control.
That would be the most consistent, and you would not tie up any mouse button.

Personally I prefer to drag with the middle mouse button in the direction that
I want to travel over the common method of moving the document about with a
hand.

> You press LEAP followed by another key and the display scrolls to the next occurence
> of that key -- it's basically incremental text search. I'd like to see that
> feature *everywhere* scrolled text is displayed.

Many text editors have this feature. JED comes to mind.

> Anyways, here are some of the things that I think are important with
> scrolling.
> 
>  * Smooth, continuous motion -- we still do way too much line-at-a-time
>    scrolling and that makes it *very* hard to read while scrolling. This
>    would be a perfect configuration option: scroll speed. It should always
>    be single pixel motion, but with a variable timer between scrolls. (The
>    API to applications should still be line at a time -- just have the app
>    render the next line into a pixmap and copy it in a scan line at a time.)
>    (Ok, I admit, some display devices are so bad that the flicker with
>    scan-line-at-a-time scrolling is worse than jump scrolling a line. That
>    should be a rare situation though -- most of our monitors work fine.)

A few features that I have seen in user interfaces for the Amiga but nowhere
else:

  * If the scrollbar is dragged too quickly, the movement is slowed down by the
    widget so that the user can see better where she is.

  * If the scrollbar is dragged slowly, and the widget is a list, the list
    scrolls slowly by itself to the closest even number of lines in the
    direction where the user last scrolled.
    This feature could be annoying if the thresholds are wrong.
    It should only scroll if the movement is small enough.
    When using the keyboard, I think smooth scrolling is better in any case
though.

  * Jumps within the document are animated, i.e. the window is moved over the
    document during a small time period. (up to half a second or so)
    This enables the user to see in which direction and how far the jump is.
    There is also an upper limit on the speed of the movement. When the limit is
    reached, only the start and the end of the jump are animated with an instant
jump
    in the middle of the motion.

>  * Add visual references to the scrollbar -- proportionally sized thumbs
>    are really nice, but so would table of contents markers (start of pages,
>    sections, chapters, etc.). Also, let me mark locations in the scrollbar
>    and then jump between them.

I have had the same thoughts. I think I should be able to click a page marker in
the scrollbar trough and the scrollbar should place itself there.

> The old Microsoft bars with the fixed size thumbs and far apart arrows were the worst.

The worst things with the Microsoft scrollbars is that they get to one end when
I  drag the knob and move the mouse cursor too far from the scrollbar.
This prevents me from scrolling as fast as I want to.
Windows 95 scrollbars still have this "feature" or whatever they like to call
it.
(I dunno about '98 and '2000)

/ Johan
  -- johan@tiq.com -- http://www.obsession.se/johan/ --