(kawa pictures) procedural interface for point and dimension?

(kawa pictures) procedural interface for point and dimension?

[Sudarshan S Chawathe]

I have a feeling I may have missed or misread something obvious, but I
didn't find an answer to:

What is the recommended way to create points (and dimensions)
procedurally in the (kawa pictures) library?

I realize that we can always use the underlying Java Point2D class to
create points, but that method seems messy given the overall simplicity
provided by the library.  A use case would be generating some random
points to be connected by lines.

By the way, I find the pictures library to be fun.  I especially like
the SVG output feature.  Thanks for adding it (and for kawa)!

Regards,

-chaw

Re: (kawa pictures) procedural interface for point and dimension?

[Per Bothner]

On 10/23/2016 03:22 PM, Sudarshan S Chawathe wrote:
> I have a feeling I may have missed or misread something obvious, but I
> didn't find an answer to:
>
> What is the recommended way to create points (and dimensions)
> procedurally in the (kawa pictures) library?

Is there any problems with just using the &P[x y] and &D[w h] syntax?

The documentation should probably be clearer and show examples that x/y/w/h are
actually expressions - they don't have to be constant:
    
    &P[(sqrt 3) (+ 5 6)]

> By the way, I find the pictures library to be fun.  I especially like
> the SVG output feature.  Thanks for adding it (and for kawa)!

Great.  I've been thinking about extensions: Text, animations,
interactive widgets would all be cool, but all involve a number
of complicated issues, so they'll have to wait.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/

Re: (kawa pictures) procedural interface for point and dimension?

[Sudarshan S Chawathe]

> Is there any problems with just using the &P[x y] and &D[w h] syntax?

No; you are right!  It was a "duh" moment on my part.

Regards,

-chaw

Re: (kawa pictures) procedural interface for point and dimension?

[Sudarshan S Chawathe]

This note is only a minor comment (perhaps too minor) on the
documentation/terminology.

> The documentation should probably be clearer and show examples that
> x/y/w/h are actually expressions - they don't have to be constant:
>     
>     &P[(sqrt 3) (+ 5 6)]

The above example would be a good aid to understanding.

On a related note, I think what caused my confusion was the tag
'Literal' next to the descriptions of &P and &D. That had me making an
analogy with string litrals, integer literals, etc. Of course, had I
read more carefully, I would have noticed the sentence right there
indicating that x and y are expressions that evaluate to integers (so my
earlier "duh" assessment of my confusion still stands).

I guess that leads to a question: Should &P (and &D) be described as
'syntax' instead of 'literal' (or am I confused again)?

Regards,

-chaw