[maemo-developers] Using the scrollbar on the N810

[From: Kalle Vahlman]

2008/2/25, josh.soref at nokia.com <josh.soref at nokia.com>:
> Kalle wrote:
>  > I don't understand this, why would the browser widget be interested in
>  > events that happen on the scrollbar widget?
>
>
> Pictures required:
[snip pretty pictures and explanations]
>  You will not find a properly functioning css3 capable web browser which
>  actually uses native widgets. They *all* synthesize them (some do more
>  synthesis, and some less, but all widgets are synthetic).

Sure, embedding native widgets is usually quite difficult to get right
or impossible. After all, the widgets are usually designed to be in a
tree with some specified container relationships and when you make
that assumption false things start to break.

But that wasn't really the issue here.

>  > That's what happens
>  > anyway, I start a drag over the scrollbar outside the thumb and the
>  > page is panned as if I dragged on the page.
>  >
>  > Unless of course (and I guess this is the case) it's not really two
>  > widgets but one widget doing funny things.
>
>
> It's not not two widgets, but it isn't a browser widget and a gtk
>  scrollbar widget. It's a browser content area and a browser scrollbar
>  widget emulating a gtk scrollbar widget, both inside a browser widget.
>
>  I'm glad you figured out the general problem.

Yes, the general problem seems to be that there is a bug in the
emulation that makes it work differently and, more importantly, in a
way that is error prone and confuses the user.

Let's take that pretty picture here:

+---------------------------------------+
|                                     |^|
|                                     |-|
|                                     |-|
|                  1                  |2|
|                                     |-|
|                                     |-|
|                                     |-|
|                                     |-|
|_____________________________________/v|
|<                 3                  >4|
+---------------------------------------+

Now let's consider the two scenarios:

 1) user pushes stylus down on 2 (the thumb) and starts dragging
 2) user misses 2, hitting the dashed area instead and starts dragging

1) is fine, works reliably (as long as the touchscreen does) and so on.

2) is where normally nothing but a "jump" in the location towards the
cursor happens (for the record, works like this on this ff3b3 I'm
writing this on). On ITOS2008/microb, the page is not jumping but
instead starts to pan.

Now, it's normally not an issue (nobody scrolls from the shaft are
anyway) but when it is difficult to hit the thumb due to it's size
(those huge pages you talked about) and the fact that the touchscreen
is a shotgun instead of a sniper rifle, it confuses the user when
scrolling actually goes to the opposite direction than what was
intended. Usually you end up multiple pages in the wrong direction,
and *poof* went your mental context of what you were doing (something
considered harmful to the user experience). This was the issue raised
originally, AFAICT.

>  > I don't see this with any
>  > other application, the scrollbar will "jump" to the direction of the
>  > stylus as expected if I start a drag outside the thumb.
>
>  > So I suppose this particular bug can and should be fixed in the
>  > browser UI / browser engine...
>
> Lots of things can be done in lots of places, some things can't be done
>  correctly in any one place. Some things shouldn't be done. And some
>  things might never be done.

Lots of words can be placed in a row but it doesn't mean they make a
really good sentence.

Or was that just a elaborate version of the notorious WONTFIX?

-- 
Kalle Vahlman, zuh at iki.fi
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