All:

I need to change a morph (actually one of its submorphs) while the morph is being dragged. Merely making the change (setting a color, say), then sending #changed, does nothing.

Making a change in, say, a mouse enter while dragging interrupt handler does cause it to take effect.

I started reading code and it looks like #changed SHOULD work, but it doesn't. Note that the hand tries to cache an image of the dragged morph to make it drag faster. I've not dug into the code far enough to fully grok all that is happening and I'm hoping that someone who knows the code can help.


I wrote a small test case and found some interesting things. It's attached. It contains only one class, a submorph of RectangleMorph, just 7 methods, and no changes elsewhere. See the class comment for instructions on how to run it. You initially get a single white rectangle at 10 at 10.

Pick it up and drag it to 0 at 0, keeping the button down. Note that at one second intervals the color and border width change randomly, as they should.  Now move it slowly away and watch how the color change and border width only apply to part of the rectangle. Note that it is the LRC. Huh?

Move it further away and drop it on the world. It turns white, as it should. Pick it up and drag it around anywhere but that funny TLC and it stays white. The #step method does send #changed to self.

The drawing of the colors at the TLC looks like a bug; maybe the morph origin is added twice to cause it to move away from the TLC? The failure of #changed to work looks like one to me too. Maybe it is the same bug?


Now modify #step by removing the comments from around the send of #alpha: so it looks like this:

	self color: (Color random alpha: 0.999);

Now drag and see it all work. This is a necessary feature since one cannot cache for fast dragging if it is translucent. But it is an ugly work around to my problem.


Put #step back as it was, with #alpha: commented out. Now go to #wantsToBeCachedByHand and change it to return false. Again, when dragged, the morph shows its changes, as it should.


However, these work arounds cause the hand to redraw the whole morph (and submorphs) at every step, a not so nice feature when the morph is more complex and it has visible submorphs.


Anyone got any ideas?

Thanks!

Dave
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