[Squeakland] pen trails over sketch

Randy Heiland heiland at indiana.edu
Wed Jan 11 07:55:49 PST 2006


Bingo.  Thanks much Scott!

On Tue, 2006-01-10 at 21:44 -0800, Scott Wallace wrote:
> At 8:24 AM -0500 1/10/06, Randy Heiland wrote:
> >Apparently I only dreamed this was possible in etoys?  In working with my
> >class at Girls Inc last night, a girl had painted an "ocean" as one object,
> >then a fish as another, then attempted to have the fish's pen trails show up
> >over the ocean.  It wasn't possible - the pen trails only showed up behind
> >the ocean - in the "world".  The same is true in Tweak it seems.  Is this
> >possible and I've simply forgotten how?
> 
> Hi, Randy,
> 
> The only objects that can bear pen-trails are "playfields", also
> sometimes called "PasteUpMorphs".
> 
> So when an object draws pen-trails, the trails appear on the
> containing playfield of the object; if its immediate container is
> *not* a playfield, then the *container's* container is used, and so
> forth up the line until a containing playfield is found.
> 
> Since the entire squeak "desktop" (a.k.a. the "World") itself is a
> playfield, that's where most pen-trails end up getting deposited.
> 
> For the example you mention, make the "ocean" be a playfield.  Give
> it a sea-like appearance by painting its "background picture," which
> you can draw/change by clicking on the playfield's "repaint" halo handle.
> 
> Cheers,
> 
>     -- Scott



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