[squeakland] Charts (was: New Graphing Tools)

[Steve Thomas]

On Mon, Oct 17, 2011 at 9:48 AM, Ricardo Moran <richi.moran at gmail.com>wrote:

> Hi Steve, thanks for your feedback :)
>
I would think you have learned by now not to encourage me :)

>
>
>> Nice work.  I like the idea of adding a number line. Some thoughts
>> comments and questions:
>>
>> If I understand your implementation, you have a horizontal and vertical
>> scale. Then you for each scale you select the "current object" you wish to
>> operate on, to sets its vertical/horizontal position to the "current object
>> position in chart" for each scale.
>>
>
> Yes, that is correct.
>
>
>>
>> I think it would be better if you could somehow set the playfield's
>> "scale" based upon the number line(s).   When you add a scale to a the
>> playfield, the objects in that playfield have their X and Y values set to
>> the scales you added.  Then if you "move forward by | N" it moves forward
>> not by N pixels but by the scale settings.
>>
>
> Well, that was my initial implementation, but as I recall Bert argued that
> it was too complicated to add another scale on top of existing scaling. And
> I have to agree with him, not only because this way is a lot less work :)
> but because it is also less error prone, my last implementation required
> patching a lot of important methods.
>
Understood (well at least at the imagining how things are
designed/implemented level).  The only concern I have is if you don't do it
this way how can you (or can you) have an objects forward by, move based on
scale settings instead of pixels?
Hmmmm...  Perhaps (warning requirement overload potential)  You could have a
move item in collection forward by tile (read further and hopefully what I
am suggesting will become clear, not necessarily the right thing to do, but
clear).

Also, I think changing the scale of the playfield based on the number line
> could cause confusion. If we follow that direction what scale would a
> playfield use if we add two number lines? The opposite is also true: having
> a different independent scale for the playfield and for the number lines can
> cause confusion as well (as Randy pointed out). So I think this is the
> simplest posible implementation: the only responsible of transforming from
> one scale to another is the number line.
>
>
>>
>>
> Another possible approach is to have a collection for each "scale". Then
>> all objects in that collection will have their X, Y values set to and use
>> those scale(s).
>>
>> It would also be nice to have "set of scales" as one object (an X and Y
>> scale) and one collection to make it simpler to add to both in one step.
>>
>
> I'm sorry, I couldn't follow you...
>

Let's say you have a scale (or pair of scales).  My thinking is along these
lines...
Each scale could have  reference to a collection of "points/things to
graph"
Then when you either:

   - change a scale, or
   - add a "point" to the referenced collection,

you then:

   - For each object in the collection:
   - change the point(s) X,Y to match the scale

The use case I am thinking of is kids plot a bunch of points, then you
change the scale, you would want the points to auto-magically adjust to the
new scale setting.

>
>>    - Perhaps have an option to show 0 (or not).  This would be useful for
>>    when you have two axis that intersect at 0, as it would look better if we
>>    didn't show the 0 labels.
>>
>> Yes, that's something I thought too.
>
>
>>
>>    - When I change the *Line's min val* it changes the max value (and
>>    vica versa).  Hmmm, okay I think I'm beginning to understand why you did
>>    this.  I was used to setting the min and max value for the axis and having
>>    the scale adjust as opposed to the scale setting the max value (well "Invert
>>    always invert" ;)  Have to think about this.
>>
>> Mmm... I don't remember why I did it like that. I guess I thought the
> scale was more important and it should be fixed, but I can change that if
> you feel it should be the other way around.
>
>>
>>    - The labels seem a little too close to the number lines.
>>
>> True. I'll fix that.
>
>
>>
>>    - It would be nice to have tiles to specify the font and size for the
>>    labels. (Or course it would be nice to tiles to specify font, size,
>>    centered/left flush|right flush|centered, for all text objects :)
>>
>> Mmm... I could add those tiles to the text objects but I'm not sure of
> adding them to the number line. Maybe I could add the "collections" category
> to the number lines and you could iterate over its submorphs changing
> whatever property you like. In fact, I think that could be added to all
> objects because all of them can behave like a collection. What do you think?
>
>>
>>    - How can you set the arrow head for the negative direction?
>>
>> Well, you can't :). But that's easy to fix. I don't remember who did but
> someone told me that the axis with the two arrow heads was confusing because
> it is supposed to point to the direction of positive infinity, but I always
> thought the arrows represent the axis going on forever, so I removed the
> negative arrow head at the time. I don't really know what is the correct
> meaning of the arrow heads but I could add a preference to turn the negative
> on/off.
>
I like the preference, with the default set to negative off.

>
> Cheers,
> Richo
>
>
>
>> Stephen
>>
>> On Sun, Oct 16, 2011 at 8:16 PM, Ricardo Moran <richi.moran at gmail.com>wrote:
>>
>>> Hi guys, I'm trying again with the graphing tools. It's been a while
>>> since I worked on this (sorry about that) but I really want to see them
>>> integrated.
>>>
>>> So now I'm following Bert's suggestions and I'm trying with a less
>>> general approach: I'm not introducing a new scale on top of the existing
>>> one, instead I just added a "current object" slot on the number lines, and a
>>> "current object position in chart" slot that transforms from squeak's pixel
>>> to the number line scale and viceversa.
>>>
>>> The implementation is much simpler than before but it's more
>>> uncomfortable IMHO. I think it would be best to have two "transform"
>>> functions accepting a number as argument and returning it transformed from
>>> one scale to the other. Unfortunately, it seems Etoys doesn't support this
>>> kind of functions nicely, all the examples I could find (such as
>>> #color:sees:) seem to be a little hacked and I wasn't sure if following that
>>> path was the right way to proceed.
>>>
>>> I think the best would be for you to test it and tell me what you think.
>>> I'm attaching a project with the new number lines.
>>> Thanks!
>>>
>>> Richo
>>>
>>> P.S. I also renamed the project to Charts as Bert suggested
>>>
>>> _______________________________________________
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>>> squeakland at squeakland.org
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>>>
>>>
>>
>
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