[Etoys] The behavior of set heading is changed subtly

Karl karl.ramberg at comhem.se
Sat Dec 15 10:12:12 EST 2007

Yoshiki Ohshima wrote:
>   Hello,
>   Lately, we are fixing various bugs reported on trac and elsewhere,
> and one of these items is:
> http://dev.laptop.org/ticket/5214
> (Try the example project made by Abe-san.)
>   The simplest fix was to remove some logic that ignores the attempt
> to set a new heading value if it is "close to" the old value.  The
> logic was from old days and we (collectively) cannot really see the
> reasoning behind it.
I think it was helpful when you rotated a morph by the handle it would 
'snap' to the old angle.

>   We can take the check out (and the change is pushed to the update
> stream already), but there is a small risk.
>   The risk is that some existing projects may change their behavior; if
> your program depends on the old behavior, where if you set a value to
> heading but it actually doesn't change it sometimes, it could be a
> problem.
>   Also, the calculation of heading after an object bounced at the edge
> is changed.  This is similar but more risky because in the old
> behavior the heading was rounded.  If your project uses equality on
> the heading value and bounce, this could be a problem.  (Now, we have
> the function tile to "round" the value, so one could create a proper
> script with it.)
>   Please let us know if this change causes a trouble.  Thank you!
> -- Yoshiki
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