[Bf-python] Ipo/IpoCurve API revisited

[Ken Hughes]

Toni Alatalo wrote:
> On Saturday 11 March 2006 23:33, Ken Hughes wrote:
> 
>>the direction that the API rewrite was taking (which apparently for now
> 
> we talked about this a bit with Ken and Jestie on irc - revisiting many issues 
> that were talked on this list last year etc. i try to summarize here a bit.
>
>>>(read-only).  Makes it possible to do "ipo['LocX']" or "ipo[Ipo.LocX]";
>>>something like ipocurve[framenum] to do current .evaluate(framenum) might
> 
> again i remembered that someone said that obipo.loc_x would be nicer than 
> obipo.['LocX'] for that and i think i agree.. (classes in py are just 
> syntactic sugar on dicts anyway, like the perl ppl say :)
> 
> how does this seem to you? just an idea..
> obipo #a object ipo
> obipo.LocX #LocX ipo: ipocu if that channel exists in this block, None if not 

After thinking about this, I don't know if this will work with tp_getset 
(or at least not easily).  I'm trying to interpret PEP 252 but it seems 
that "__slots__" might allow per-instance attributes, if only I can 
figure out how to implement them.

> i think None is similar to the grey thing that you see in the UI, and LocX is 
> same as in ui, unlike the loc_x that i would like for other resons)
> obipo.Col #rises NameError - object ipos dont have color channels, only 
> texture ipos do.
> 
> then the perhaps weird part:
> obipo.LocX[10] = 1 #if LocX was None, creates a new ipocurve there, and sets a 
> keyframe / bezcu control point to position 10, with value 1 - otherwise 
> modifies the existing curve, either creating a new keyframe, or modifying an 
> existing one.
> 
> .. i understand it can be bad to have such drastic side-effects from just 
> assigning a number, but that is how the UI works: if you wanna key the 
> location, you just insert a key to location. and i guess that is what 
> scripters often do too..

While this seems simpler for the user (like Johnny's implmentations of 
insertIpoKey()), I'm thinking about it from the beztriple side also. 
Which is more important; the curve's value at some particular frame more 
important, the bezTriples making up the curve, or are they equally 
important (or unimportant)?

Ken

> 
> this might be more normal Python:
> obipo.LocX = IpoCurve()
> obipo.LocX[10] = 1
> .. but why should a scripter have to know the name of the curve class to just 
> add keys..
> 
> also, this might be a cool shorthand:
> obipo.Loc[14] = (x, y, z)
> 
> for:
> obipo.LocX[14] = x;
> obipo.LocY[14] = y;
> obipo.LocZ[14] = z; 
> 
> also similar to UI, where you can just key the location with a single 
> keypress..
> 
> typing these [framenum] things to the curves feels a bit strange, but i guess 
> that would be the possible option .. obipo[14].Loc makes no sense. feel free 
> to judge if any of this does :)
> 
> .. Ken is gonna implement something anyway.
> 
> 
>>>i guess you saw http://orange.blender.org/blog/from-ipo-to-ipo ?
> 
> 
> the final code for that thing, animation code for the switchboard set in the 
> elephants dream, is still at 
> http://www.blender.org/~antont/makewireipos.py .. and i think this kind of 
> api would have been nice for making it. dunno about how they would seem from 
> the perspectives of other needs, tho.
> 
> 
>>>~Toni
> 
> 
> same.
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