What are hSscroll, vScroll really?

[J. Landman Gay]

On 12/8/12 10:50 AM, Graham Samuel wrote:
> This is a comment that the LC documentation has not (yet) delivered
> the goods. I think there's a bit missing (I've tried the user guide,
> the release notes and the dictionary by searching for the words
> 'scrolling' and 'scroller').
>
> In the LC dictionary, it says this about hScroll (the horizontal and
> vertical scrolls are the same in principle so I'll just quote the
> entry about h):
>
>> The hScroll is the amount in pixels the object has been scrolled to
>> the right. If the hScroll is zero, the object has not been
>> scrolled.
>
> Er yes, but what is the implied context here? If I create a group (or
> a field) and plonk it onto the middle of a card, can I make it move
> to the left or right by changing its hScroll, regardless of any other
> objects on the card? The answer is 'no' - but the LC docs doesn't
> explain the underlying context, so one can be left confused by this
> definition.

That would be a good candidate for a user note entry I think. The docs 
are assuming that the user is familiar with the concept of scrolling, 
which I don't find too far off. It's probably clearer if you think about 
a scrolling field. The location/position of the field never changes, it 
always remains in the same place on the card. Only the viewable content 
changes. The offset of the content is the scroll.

Since the concept is universal on all computers, I can understand why 
the docs don't specifically define it though I suppose it wouldn't hurt. 
What I do think is missing in the case of mobile scrollers is a specific 
statement about how it is a transparent overlay that only sends 
information about user actions; it doesn't actually manage objects on 
the card.

Before I answered the original question I did a search through the RR 
lessons and was surprised that iOS scrollers weren't addressed. Most 
other iOS concepts are there. Scrollers are widely used and there should 
be an entry in the lessons about it.

-- 
Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com