Hi Andrew,
Just wanted to point you to my previous reply
http://lists.squeakfoundation.org/pipermail/squeak-dev/2007-May/116371.htmlAnd I found some of my wip code that my serve as a
good example and placed it on bob's superswiki here:
http://209.143.91.36/super/728aka
http://209.143.91.36/super/MovingPiece-wizIts in the form of a project meant to work in 3.9
(7067).
HTH.
Yours in curiosity and service, --Jerome Peace
***
>
>
> Another stupid Morphic Question
> Andrew P. Black black at cs.pdx.edu
> Tue May 1 16:03:44 UTC 2007 wrote:
>
> On 1 May 2007, at 1:07, Andreas Raab wrote:
>
> > ... it's the world which implements the default
> behavior of
> > dragging objects. In other words the action is
> contextual (objects
> > in the world can be dragged) not builtin.
>
> Aha! This was an insight that I was missing.
Someone
> should write a
> book that explains all this stuff ;-)
>
Why not start a wiki page.
You can either copy from the mail or use hypertext to
point to the relevant emails in the archive.
> > This code seems both overly complicated as well
as at
> least
> > somewhat buggy (grabMorph:from: should only be
used
> for owner-less
> > morphs). Try the following instead:
> >
> > rect := RectangleMorph new.
> > rect extent: 100 at 100.
> > circle := EllipseMorph new.
> > circle extent: 100 at 100.
> > rect addMorphCentered: circle.
> > rect on: #mouseDown send: #value to:["ignore
drags"].
> > circle on: #mouseDown send: #value
> > to:[circle world primaryHand grabMorph:
> circle].
> > rect openInWorld.
>
> Well, this is much more elegant: the use of
on:send:to:
> simplifies
> things considerably, and, along the way, explains
how
> to use
> EventHandlers, which were another mystery. But it
has
> the same bug:
> once the circle has been "picked up", it is no
longer a
> submorph of
> the rectangle. Presumably that could be fixed by a
> #mouseUp handler,
> although I tried adding
>
> circle on: #mouseUp send: #value
> to:[rect addMorph: circle].
>
> which appeared to have no effect.
> >
> >> I could probably find all of the bits of code
that I
> need, to
> >> handle mouse move and so on, taking care of the
> offset between
> >> mouse click event and the origin of the Morph
that
> I'm moving
> >> most of the code must be in HaloMorph. But this
was
> the Default
> >> Behavior of the circle before I embedded it in
the
> rectangle
> >> surely there must be an easier way to get that
> default behavior
> >> back, other than duplicating the code from
whereever
> it is hidden!
> >
> > Well, by far the easiest way is to use a
PasteUpMorph
> instead of a
> > RectangleMorph - PasteUps have this behavior
builtin.
>
> That is the answer I was looking for! Inter alia,
it
> explains what a
> PasteUpMorph is for, somthing that I had never
> appreciated (except to
> know that the World was one).
>
> Thank you!
>
> Andrew P. Black
> Department of Computer Science
> Portland State University
> +1 503 725 2411
>
>
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