Re: [Usability]Re: An alternative proposal for instant-apply vs. non-instant-apply

[Liam Quin <liam holoweb net>]

On Sat, Sep 08, 2001 at 11:15:38AM -0700, Adam Elman wrote:
> The relevant interface design principle here is called "direct 
> manipulation."  Direct manipulation means that user actions have 
> immediate effects.  This gives a user the feeling that their actions 
> are having a direct effect on their environment, which:

Direct manipulation means that yuo operate on a representation of
an object, not on a parameter that describes the object.

Example: dragging an icon s a dierct manipulation of that icon.

Dragging an icon representing a file onto an icon representing a
waste-paper basket is a gesture-based way to delete the file, but is
not direct manipulation (if it just deleted the icon, and not the file,
it would be direct).  A better way to delete a file might be to pick
up a picture of the red marker pen and draw an X over the file's icon :)

When you move a slider to change the value of a number, that's derct
manipulation of the value.

When you enter "red" into a dialogue box, and the colour of your
scrollbars changes, that's not direct anything except that you
are manipulating the string "red" dierctly by typing it.

When you drag a red colour swatch onto a scrollbar and it recolours,
you are manipulating the colour "red" directly.

I'm sorry for the very basic examples here.  I am trying to prepare for
the following statement:

    Almost all Gnome dialogue boxes do not involve direct manipulation.

Now, I *do* agree with you that changing setting directly is a good thing
when it can be done.  The scrollbar example above might be a good example,
although most people migh (this is a guess) prefer a "playpen", a
theme designer, where they use direct manipulation to create a theme,
and can then apply the theme to one or more programs or windows or
whatever makes sense.  With Undo universally available, people would have
more confidence to explore.  Sun used to have an Undo key on their
keyboards (maybe still do), and when it worked for almost everything,
it was very effective.  It even worked (in openwindows) for deleting files.

Direct manipulation was a big step forward in inerfaces, and I don't
think we need to argue about that.  I would go further and agree that
reducing the number of dialogue boxes is a win.  They break the metaphor;
in theatrical terms, they are part of the staging mechanism:

    Hamlet has finished speaking and
    is leaving the stage.
			[OK] [Cancel]


would be very distracting (and confusing, don't ask what Cancel does!).
Or to speak to a younger generation :-) heer's the Matrix version:

    Morpheos 1.2 Pill options

     Red pill: [capsule] [tablet] [caplet]     [set colour...]
    Blue pill: [capsule] [tablet] [caplet]     [set colour...]
    [Apply] [Reset] [Go back to the film and stop bothering me]



Where there is a dialogue box for settings, one compromise approach
is to give it a "preview" area that's updated automatically.  Some
image programs do this -- e.g. it's one reason why  PaintShop Pro
is so popular on Windows; Gimp does it e.g. when you save a JPEG file.
Then you can support direct manipulation inside the dialogue.

Of course, one reason PaintShop Pro does this is that it can take a
long time to run an unsharp mask filter on a 60 megabyte image (somthing
I was doing last night by the way).  Luckily I had an IRC window
visible too ;-)  There is no reason to believe that this will change:
a computer 100 times faster could run that unsharp mask in a few seconds,
but then you'd be saying, "I want to see Robert Redford play Neo in
this film", but re-rendering might take several minutes.

So we need both paradigms.

Sometiems dialogue boxes are not really like operating a radio.  They
are more like baking a cake ;)  You have to get all the ingredients mixed
right before you cook.  "Instant baking" when you add an ingredient
would not work.

You can always find examples that work better one way or another.

What are the ten most-used "gnome" applications?
gmc, gnome-terminal, gnumeric, then what? gnozip? eog? pam?
If my experience is typical, then not yet evolution (crashes too much),
and probably not nautilus (too slow, confusing interface).

So maybe use dialogue boxes from gmc, gnome-terminal, gnumeric etc in
examples, and let's see if there's less controversy over those.

If I change units from Imperial to metric, or change floating point
accuracy, should the entire spreadsheet recalculate each time I type
a digit in the "accuracy" box?  Or, if it's a slider, should the
figures change while I am sliding?  It would be nice, as long as
the dialogue box could bemoved around so I could look at the
intermediate results.  If I change denominator and numerator in
a fixed-point accuracy preference, I have to change both, as otherwise
my data could be damaged from ruonding errors or overflow.  So
there again, maybe both are needed.  (Undo is only OK if the user
knows when it's needed)

Best,

Lee


-- 
Liam Quin - XML Core staff contact, W3C, http://www.w3.org/People/Quin/
Ankh: irc.sorcery.net www.valinor.sorcery.net irc.gnome.org www.advogato.org
Author, Open Source XML Database Toolkit, Wiley August 2000
Co-author: The XML Specification Guide, Wiley 1999; Mastering XML, Sybex 2001