Dan,
i've built a subclass of ScrollPane called PluggableScrollMorph that takes
any ol' morph to be displayed inside the scroll region. in doing this,
however, i've run across a snag. i've described the problem below. i have
also attached the changes i have made to ScrollPane. if i am on the wrong
track, the please set me to rights. if not, i'd like to submit my changes to
be included in the next set of updates.

when i first starting playing around with ScrollPane morphs, i thought that
adding a morph to the scrollable region would be as simple as something like:

   ScrollPane new
     addMorph: (EllipseMorph new extent: 50 at 300);
     openInWorld

while playing around with Morphic and trying to get familiar with everything
i discovered that i could do the same thing interactively in a Morphic
Project by:

   World->new morph...->Basic->EllipseMorph
   EllipseMorph->resize
   World->new morphs...->Windows->ScrollPane
   drag EllipseMorhp on top of ScrollPane
   EllipseMorph->embed... ScrollPane

both of these give me the same thing: a result other than the one i was
hoping for--the EllipseMorph sits on top of the scroll pane, not inside the
scroll region.

when building the ScollPane interactively, i noticed that when i went to
embed the EllipseMorph inside the ScollPane i could choose to embed it
inside some unnamed TransformMorph and i was closer to the result i wanted.
rummaging through source code in the image i found that the programmatic
equivalent was to ask the ScollPane for its scroller and put the
EllipseMorph there.

   | pane |
   pane := ScrollPane new.
   pane scroller addMorph: (EllipseMorph new extent: 50 at 300).
   pane openInWorld

well, there was two problems with this. number one, i didn't like it. it
seemed like a violation of encapsulation to know that you needed to ask for
scroller to add your morph to. number two, when you add your morph to the
scroller, the ScrollPane doesn't know to update itself, so the scollbar
doesn't adjust itself.

so, i "fixed" both of these problems by rewriting addMorph: in ScrollPane to
add new morphs to the scroller and then update itself. (i also had to make
changes to initialize.)

and it was Good.

until, in the course of building PluggableScrollMorph i realized that maybe
it wasn't as easy as that. now that the submorphs are all inside the
scroller, i see that i'll need to rewrite quite a few methods that get
inherited. the first one i came across was replaceSubmorph:by:, but it looks
like there are quite a few more. in addition, there are quite a few methods
(200+) in the Morph heirarchy that reference the submorphs instance variable
directly; these should probably get the collection of submorphs by calling
an accessor method that can be overridden for container objects like 
ScrollPane.

so, i'm not quite sure if i am on the right track. let me know what you think.

david

At 09:44 PM 6/21/99 -0700, you wrote:
>Folks -
>
>You may have noticed Squeak Central laying low through the last couple of
mail storms.  It's not that we're not interested, it's just that we have
been busy.
>
>We have made some progress in integrating balloon with morphic, integrating
3D with morphic, and integrating normal programming with scripting and
viewers.  Also a unification of WorldMorphs with PasteUpMorphs so that any
world or pasteUp can be written out to a SqueakPage, and then read in as a
world, a pasteUp, or the page of a book.  Also some steps toward better
modularity, such as being able to atomically assert/revert changes when
entering/leaving a project.  And some fun new stuff in music that lets you
enter melodies from a keyboard into a score, and then copy and paste them
and play the results, as well as some tweaks that make it easier to play
with looped sampled sounds.
>
>It's my hope to assemble all of this into a new image some time next week,
but it might take a bit longer as several of the changes touch a lot of
code.  We have lots of updates to put out, and I will probably release a
spate of them toward the end of the week.
>
>A number of interesting enhancements and bug fixes have been put forward
from this mailing list.  Please let me know privately of anything you feel
deserves special consideration for inclusion in the main line release.
>
>In case you wonder, everyone here resonates with the desire to spruce up
Squeak.org, and to clarify our mission a bit in the process, but we probably
won't take any real action until we have put out the next release.
>
>Walk tall and talk Small
>
>	- Dan
>
>
>

Attachment converted: Anon:ScrollPane.26Jun536pm.cs (TEXT/MSIE) (0000AD11)

--
         j. david farber
     oo architect+mentor
numenor labs incorporated
in sunny boulder colorado
     dfarber at numenor.com
         www.numenor.com