[squeakland] Possible Bug?

Bert Freudenberg bert at freudenbergs.de
Fri Feb 2 13:58:24 UTC 2018


Hi Jeremy,

it looks to me as if it works fine if you remove the second line in this
script:

[image: Inline images 3]

You might also try to replace it with setting bottom instead of y.

The source of this is likely that in Etoys y goes up but in Squeak it goes
down, so in various places of the system it has to be inverted. That causes
truncation to sometimes round up or down. Which apparently accumulates some
error. Not trivial to fix.

- Bert -

On 26 January 2018 at 22:49, Jeremy Landry <hakyoku at gmail.com> wrote:

> I haven't investigated it into the Etoys source, but I found this bizarre
> bug, likely appearing due to a number being turned into an integer when
> it's odd, but I cannot figure out why it would be called at all...
>
> Included is a project that demonstrates this bug.  I looked at the
> individual pieces and they aren't 'personally' responsible, but when
> working as a unit, they then exhibit the bug.
>
>>  custom window demos.013.pr
> <https://drive.google.com/file/d/1nefep7r-gSbJ5xyLGKbWUU54ozFlzNid/view?usp=drive_web>
>>
> Basically what seems to cause it is resizing nested playfields via
> script.  R​​esizing with morphic handles works fine, but when sending an
> Etoys 'LENGTH' change, somewhere along the line, things go wrong.  Again,
> my guess is that some number is getting changed into an integer from a
> floating point, and thus getting rounded up, which would shift it up when
> it's not a floating point number any longer.  However, this doesn't explain
> why it doesn't have the same symptom when changing WIDTH.
>
> Thanks for any insight into dealing with this.  I'm not exactly sure where
> to begin looking within the Etoys Source to make things work as expected
> since there's likely 30 reasons (read: random object methods) why this
> might occur and only for vertical change/LENGTH change.
>
>
>
>
>
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>
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