[etoys-dev] x-y plane questions

Scott Wallace scott.wallace at squeakland.org
Mon Mar 19 02:38:52 EDT 2012

On Mar 18, 2012, at 5:52 PM, Ricardo Moran wrote:

> I made a couple of changes to the number lines that I would like you to check:

I've looked quickly tonight and hope to have more time tomorrow, but a quick reply for now, hoping others will chime in soon.

> * I added two tiles: "transform to pixel" and "transform to graph" (the names could be improved but I didn't know how to name them). This tiles take a number as a parameter and return it transformed to the other coordinate system. It's a general way of using the number lines and I think it could be very useful.

This certainly expands the bounds of what can be done with number-lines.  Cool example too :)

Since "transform to pixel" provides a transformation from a number-line-based coordinate to a coordinate in the cartesian system of the surrounding Playfield, perhaps it could be called "transform to playfield"?  Not sure if that's much better, if at all, however.

If we adopt these new guys, we'll need to provide balloon help of course...

> * I changed "x on graph" and "y on graph" to take into account the object's rotation center. However, I could have messed up with this and it could have undesired side effects, so testing would be needed.

Oh, good idea!  Thank you!

Good stuff!  The irrepressible Richo - what an asset to the community!

  -- Scott

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