Re: [Dynapi-Help] What is enableBlackboard?

[<do...@cr...>]

More verbose.. also checked code to verfiy.. the part about a transparent
coverlayer was just smoke (won't say what kind of smoke..)

So.. 

As we know, if you add a child layer or widget to a layer, then set the html
of that layer, the existing html (the child ler or widget) get's deleted.
Obviously this can cause some issues if your coed expects said layer or widget
to be there.

The solution to this is to call enabledBlackBoard on the parent layer.
Having done this, when you call setHTML() on a layer that has it's Blackboard
enabled, the html that you specify is placed within the blackboard instead of
replacing the html of your parent layer.

Man reading the above just confuses me.. and i wrote it :-)
new visual:

case 1 (no blackboard)
create a layer and add a widget:
(result)
[myLayer]
    [myWidget][/myWidget]
[/myLayer]

then call myLayer.setHTML("where's the widget?")
(result: note the widget is gone)
[myLayer]
    Where's the widget?
[/myLayer]

case 2 (with blackboard)
create a layer, add a widget, enable blackboard
[myLayer]
    [myWidget][/myWidget]
    [_blkBoardElm][/_blkBoardElm]
[/myLayer]
then call myLayer.setHTML("there's the widget!")
[myLayer]
    [myWidget][/myWidget]
    [_blkBoardElm]there's the widget![/_blkBoardElm]
[/myLayer]

One thing i do notice while looking at the code is that we do not specifiy the
Z-Order of the blackboard. This can cause a problem if the blackboard is added
after a widget or childlayer has been added as the blackboard may overlap said
child layers.

notes:
if blackboard is enabled after a sethtml call (or layer is created with
default html in the new dynlayer() call) then the html will be transferred to
the blackboard.

Recommend specifying a largely negative Z-Order on the blackboard layer

Cheers

Leif W <war...@us...> said:

> > From: <do...@cr...>
> > Sent: 2005 August 24 Wednesday 11:06
> >
> > here it is.. the blackboard as described below is to allow you to add 
> > a child
> > layer to a layer, and then later call sethtml on the parent layer 
> > without
> > accidently deleting the child layers :-)
> 
> >> before EnableBlackboard()
> >> [myLayer]content[/myLayer]
> >>
> >> After EnabledBlackboard
> >> [myLayer]
> >>    [TransparentCoverLayer]
> >>       [BlackBoard]
> >>          Content
> >>       [BlackBoard]
> >>    [TransparentCoverLayer]
> >> [myLayer]
> 
> Wow, excellent, thanks for that explanation and visual.
> 
> Leif
> 
> 
> 
> 
> 
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