[etoys-dev] x-y plane questions

[Ricardo Moran]

I forgot the project in the previous mail :P.

Richo

On Sun, Mar 18, 2012 at 9:52 PM, Ricardo Moran <richi.moran at gmail.com>wrote:

> Hi,
>
> I made a couple of changes to the number lines that I would like you to
> check:
> * 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.
> * 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.
>
> I attached a project that uses the x-y plane for ploting bars (open it on
> Etoys 5.0 beta 2).
>
> Cheers,
> Richo
>
> P.S. I just found the "attached watcher" option and it's great!
>
> On Sun, Mar 18, 2012 at 6:16 PM, Scott Wallace <
> scott.wallace at squeakland.org> wrote:
>
>> On Mar 18, 2012, at 6:12 AM, Steve Thomas wrote:
>>
>> > But I couldn't figure out how to change the pixel width of the graph
>> paper, could you point me in the right direction, thanks
>>
>>
>>
>> Hi, Steve,
>>
>> Open the attached fileout in a change-list browser (click "changes"
>> button in file-list); the diffs that will show between the versions in the
>> fileout and what's in the image will answer your question :)  In the
>> versions I've sent, the grid-line-width is parameterized instead of
>> constant, and in both cases, for illustration, that grid-line-width
>> parameter is set to 2.
>>
>> If wider-than-single-pixel grid lines seem viable and useful and don't
>> introduce new issues (need to be sure to test everything with "scale to
>> fit" turned on), perhaps we could add the grid-line-width as another
>> parameter in the graph-paper panel.
>>
>> With scale-to-fit on, it seems that with both 1-pixel and 2-pixel
>> grid-line widths we end up with round-off phenomenon such that some of the
>> grid lines are thicker than others.  I'm not sure if this is an intractable
>> mathematical consequence or something fixable, but I suspect that it's the
>> former.
>>
>>  -- Scott
>>
>>
>>
>> _______________________________________________
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>> etoys-dev at squeakland.org
>> http://lists.squeakland.org/mailman/listinfo/etoys-dev
>>
>>
>
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