Newbie Questions

Bert Freudenberg bert at isg.cs.uni-magdeburg.de
Fri Jul 4 17:32:32 UTC 2003


Am Freitag, 04.07.03 um 16:42 Uhr schrieb Ned Konz:

> On Friday 04 July 2003 07:36 am, Lic. Edgar J. De Cleene wrote:
>
>> You could test color in world withour using e- toys like in a
>> following.
>>
>> [(World colorAt: (self center)
>>         belowMorph: self) = Color yellow]
>>
>>
>> Replace self center for choosen point of control.
>
> But that doesn't work on the turtle trails, as far as I can tell. The
> implementation of PasteUpMorph>>patchAt:without:andNothingAbove: just
> does a background fill and draws the submorphs. It skips the
> turtleTrailsForm completely (unlike drawOn:).

By looking at the implementation I thought that, too. But actually it 
works, at least in a playfield. This is because a patch of the World is 
examined, which includes the playfield and its turtle trails.

To make that work on the World itself it is sufficient to draw the 
world itself onto the ColorPatchCanvas. I can see no good reason why 
one would not want to do so. See the updated changeset in my next mail.

-- Bert



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