[etoys-dev] New Graphing tools

Steve Thomas sthomas1 at gosargon.com
Sun May 22 23:25:52 EDT 2011


Love it!  I especially like the idea of scaling (I think Karl had an idea
like this a while back as well).
Interesting how setting x to 0 has 0 = 2.220446049250313e-16 (close enough
+/- epsilon?)


On Sun, May 22, 2011 at 3:49 PM, Ricardo Moran <richi.moran at gmail.com>wrote:

> Hi guys, following Bert's request I've resumed some of my work for GSoC
> hoping that it could be included in the next Etoys release :)
> This is a new version (a complete rewrite, actually) of the graphing tools.
> This time I've followed Steve's idea of a simple number line object and the
> ability to change the scale of the playfield so that kids could make their
> own graphs (you can find the original conversation in this old thread<http://answerpot.com/showthread.php?899620-Copying+Graphing+tools+and+Speech+Bubbles+to+Inbox>
> ).
> You can see in the attached project that the playfield includes two new
> objects (horizontal number line and vertical number line). This objects have
> an extra category called "number line" with a few properties such as:
> * increment
> * min/max value
> * scale
> You can change the scale to define how much pixels will mean a unit of the
> number line. The increment will define the distance between labels.
> You will also find a new category on Playfield named "coordinate system".
> This category has:
> * origin at center?
> * origin
> * scale x
> * scale y
> Using this properties you can define a different coordinate system for the
> objects you throw inside the playfield.
> In the attached example I defined a playfield with the origin at 50 at 50(this means 50 pixels from the bottom and left sides), an x scale of 1, and
> an y scale of 30. You can see how the position of the star changes acording
> to this scale while you move it inside the playfield and how it returns to
> its original scale when you pick it up and drop it outside the playfield.
> For now it's just a proof of concept. A lot of things still don't use this
> new scaling (i.e. #forward:). But I want to know what you think about this
> direction.
> Also, how much time do we have until the deadline? I have two exams
> tomorrow so I'm probably off for today. We can discuss this stuff at
> SqueakFest :)
> See some of you in Montevideo!
> Cheers,
> Richo
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