Reading again the listGroup behaviours recently (30.3), I was surprised and
diappointed by a few things :
1. Update behaviour, paragraph 2
I don't understand why it says that position is set before the item is
deactivated. It is simply illogical IMHO. Usually, MHEG always undo things
in the exact reverse order they were done. Here, it would have been logical
to deactivate the item and then to set its position to its original
position, not the opposite !
Consequently, current behaviour normally produce weird display oddities
since you can see items moving before being stopped. (Remember that
offscreen buffer allowing the LockScreen/UnlockScreen is not mandatory for
an MHEG engine).
2. Update behaviour
I think it is a shame that ListGroup only manage the position attribute
with its cells, and not the presentation priority (display stack).
Suppose you want to build a ListGroup with wrapAround true, and which use
cells that are stacked a bit (for instance an address book or a kind of
jukebox where you can see the frontmost cell entirely and the following
partially.
To allow the wrapAround attribute, the author have to manage the
presentation priority with putBehind, putBefore action which would have
better been done by the update behavior IMHO.
3. AddItem
I think the addItem action/behaviour would have better been splitted in 2
actions/behaviours : AppendItem and InsertItem.
Most of the time, you want to add an item at the end of a listGroup. I
think that it is stupid that the author must use 3 elementary actions to
simply append an item to the list :
GetListSize(listGroup, index)
Add(index, 1)
AddItem(listGroup, index, item)
It would have been better to have an insertItem just like the current
addItem, but also an appendItem that don't need an index but simply add the
item at the end of the itemList.
My last question is about MHEG development:
Why is it so long to have any clarification or modification in MHEG-5 ?
Some problems discussed more than 1 year ago are still not clarified
officially. I do think that we cannot continue to all use MHEG-5 if it is
so long to make it evolve ! I'm not part of the discussion group and I
understand it is not simple with ISO but look at the way HTML standard
evolve nowadays. Perhaps ISO should have a look on W3C methods...
Best regards,
Emmanuel
__________________________________________________________________
Emmanuel BEUQUE mailto:ebeuque@pratique.fr
MediaServ tel: +33 (0) 2 99 64 35 64
Multimedia consultant & developer fax: +33 (0) 2 99 64 36 65