Re: GUI design of 0.7

[Bernhard Herzog]

Pieter Edelman <address@hidden> writes:

> Suppose you have a spiral object with three twists and you want to make it 
> five. So you bring up the dialog for changing the number of twists. Let's say 
> we use a text input field for that. Now there are two options:
> - The moment you enter "5" in this text field, a new spiral with five five 
> twists is drawn. I call this "autoupdate". I'm not sure if this is the 
> correct term.
> - The moment you enter "5" in the field nothing happens. Only when you hit 
> the 
> "apply" button on the dialog, a new spiral with five twists is drawn. I call 
> this "manual update". Again, not sure if this is the correct term.

Or: The moment you leave the entry widget, e.g. by switching to another
widget with the TAB key or clicking into another entry widget, the
changes are applied automatically.  This is what the GNOME human
interface guidelines (HIG) suggest.

A better example -- better in that it avoids the extra complications of
entry widgets -- of auto apply would be a spin button for the number of
twists.  The spin button has two little buttons that increment or
decrement the number.  After each click on one these buttons the new
number of twists is applied automatically.


> BUT, if the updating takes some time (let's say, more than half a
> second), it can become very annoying in some cases. For example if you
> want tho have 50 twists, the spiral is redrawn as you type "5" and
> again if you type "0".

The HIG say that changes in an entry widget should be applied when the
user leaves the widget.  In you example there would be no redraw after
entering the 5.  There wouldn't be a redraw after entering the 0 either.
Only after you, say, click on some other widget the panel applies the
changes to the drawing.

> Or if you want to use a slider, in which case redrawing occurs at
> intermediate steps.

I don't think the HIG demand that.  It would suffice to update the
drawing after the user releases the mouse button.  That would still be
auto-apply (or "instant apply" as the HIG call it), IMO.


> In these cases it is more convenient to turn of auto-update and press the 
> "apply"-button (or better, the "preview" button) when you think you're ready 
> for it.

The term "auto-update" is a bit misleading.  As you use it, it means
that changes to the dialog are applied without the user having to press
an Apply button.  A different meaning would be that the dialogs is
automatically updated when the selection changes.  The latter is how the
term is used in 0.6.

   Bernhard

-- 
Intevation GmbH                                 http://intevation.de/
Skencil                                           http://skencil.org/
Thuban                                  http://thuban.intevation.org/