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Re: rangeslider, a "Tale of Two Thumbs"

From: Joseph Scheuhammer <clown@utoronto.ca>
Date: Tue, 22 Apr 2008 11:37:41 -0400
Message-ID: <480E0645.6020406@utoronto.ca>
To: "Wlodkowski, Thomas" <Thomas.Wlodkowski@corp.aol.com>
CC: Aaron M Leventhal <aleventh@us.ibm.com>, David Bolter <david.bolter@utoronto.ca>, wai-xtech@w3.org, wai-xtech-request@w3.org

Tom wrote:
> Feel free to propose a keyboard behavior and then join a style guide 
> call held Tuesdays at noon Eastern and we will discuss.

Here is a first draft of a proposal.  Basically, I've taken the key 
strokes for a "single-thumb" slider and adapted it for a dual thumb 
slider.  The keystrokes for the single thumb slider are:
http://dev.aol.com/dhtml_style_guide#slider

Two Thumb Slider
- Tab to the slider's low-range thumb.
- Second tab moves to high-range thumb.
- Third tab away from slider.
- Shift-tab moves back to low-range thumb if focus is on the high-range 
thumb.
- With focus on a thumb:
    - Right and Up Arrows increases the value of the slider constrained 
by the
      value of the other thumb.
    - Left and Down Arrows decrease the value of the slider constrained 
by the
      value of the other thumb.
    - Home and End move to the minimum and maximum values of the slider
      constrained by the value of the other thumb.
    - Page Up and Page Down optionally increment or decrement the slider 
by a
      given amount, constrained by the value of the other thumb.

- Note: Focus is placed on one of the thumbs of the slider.
- Note: The two thumbs are in the focus order.
- Note: Localization for right to left languages may wish to reverse the 
left
  and right arrows.


A couple (non-keyboard) problems:  First, how does the system 
communicate to the user which thumb has focus?  Visually, this is easy; 
however, it's not clear how to do it for non-visual users.  Secondly, 
the value of the slider is not a single number, but a range.  Is there a 
common way to present a range?

If the user conceives of the dual thumb slider as a pair of separate but 
linked single thumb sliders, then the keyboard behaviour remains as 
outlined above.  The two sliders' values together define the range (the 
value of the analogous two-thumbed slider).  Perhaps the non-visual 
presentation is much that same as that for a single slider, taking into 
account that the second slider/thumb constrains the range/value of the 
system.

-- 
;;;;joseph

'This is not war -- this is pest control!'
      - "Doomsday", Dalek Leader -
Received on Tuesday, 22 April 2008 15:38:54 UTC

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