[etoys-dev] New Graphing tools

Ricardo Moran richi.moran at gmail.com
Sun May 22 15:49:19 EDT 2011

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

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

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!
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