[squeakland] Etoys programming question, clear pen trails from a textfield.

David Corking lists at dcorking.com
Thu Jan 10 11:15:00 EST 2013

R.D. Latimer wrote:
> I hope this is the correct list for etoys questions...

Yes. Welcome back!

You later wrote:
> No need for help on pen trails anymore.  I found the 'clear pen
> trails' in the 'pen trails' section does the trick.

That is great news. (How did you find it?) In the meantime I wrote up
a fuller answer which I post below in case it helps someone else with
a similar question.

I can't reproduce your problem with a 'Text' from the supplies flap.
(Both buttons work to clear the pen trails.)

However I tried with a 'Playfield' and that has slightly surprising behaviour.

Unlike most other objects, a playfield has two similar sounding tiles
in its viewer: 'Playfield clear all pen trails' and 'Playfield clear
pen trails'. They sound similar but don't do the same job. (Note the
word 'all'.)

The first tile, 'Playfield clear all pen trails', clears trails drawn
in the world, but leaves trails drawn inside the playfield intact.
(The balloon help and the reference manual say 'Clear all trails in my
containing playfield'. The world is another playfield.)

The second tile, 'Playfield clear pen trails', clears only those
trails drawn inside the playfield, and leaves all other trails intact.
(The balloon help here is 'Clear all the pen trails in the interior'.)

(For comparison, 'Car clear all pen trails' will clear all the trails
in the playfield the car is currently in.)

I tried this with Etoys 5.0 - so please mention if you notice
different behaviour on other recent versions of Etoys.

Have fun! David

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