[etoys-dev] New Graphing tools

karl ramberg karlramberg at gmail.com
Mon May 23 09:05:00 EDT 2011

I was thinking of using 'forward' together with griding so 'forward' would
mean move one grid space, not one pixel.
I have been thinking of the unit pixel in Squeak and how it is not really
explained anywhere I know of.


On Mon, May 23, 2011 at 5:25 AM, Steve Thomas <sthomas1 at gosargon.com> wrote:

> Ricardo,
> 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?)
> Stephen
> 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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