Posted by Sean P. DeNigris on Feb 04, 2015; 8:30pm
URL: https://forum.world.st/Question-on-Morphic-drawOn-method-tp4803695p4803743.html

HilaireFernandes wrote

First you don't need to subclass EllipseMorph...
100 to: 50 by: -1 do: [ :x |
    aBall
        height: x;
        bottom: 200 - x.
    World doOneCycle]

Of course you can have the best of both worlds by using Morphic stepping in your subclass, like:

EllipseMorph subclass: #Ball
...
Ball>>#step
    self
                bottom: 200 - self nextHeight;
                height: self nextHeight.
               
        self bottom = 100 ifTrue: [ increment := -1 ].
        self bottom = 150 ifTrue: [ increment := 1 ].

For full code:
    Gofer it
        smalltalkhubUser: 'SeanDeNigris' project: 'SeansPlayground';
        package: 'Ball';
        load.