Re: LOGO-L> Re: Logo Contest Entry

[George Mills <mills@softronix.com>]

Craig Denson wrote:
> 
> george
> 
> >>  repeat 100 [ setpencolor 1 + random 8
> >>               repeat 11 [for [i 0 359] [fd 1 rt (sin :i /  2)]]]
> >>
> ...
> >setpencolor is not a single index it's a list of [red green blue]
> >
> >I personally do not like much code on one line because it's too hard to
> >read and debug. You had 1 to many "]"'s also.
> 
> thanks for the response - but i did this using ucblogo on a unix box
> and it works as written. i was mostly interested in why it >appears<
> to be a closed figure, although your suggestion for smoothly varying
> colors is worth trying on a pc.
> 
> a comment about setpencolor is that it seems too complicated to do
> simple color changes. don't get me wrong, i like the flexibility, but
> i might have considered a bit of indirection by having, say a palette
> command that reconfigured the choices and leaving setpencolor to take
> a single number as input. eg.
> 
>  palette [index | list of indices] [rgb vector | list of rgb vectors]
>  setpencolor index
> 
> heck, you could have a third parameter that toggled the color space
> between, say rgb, cmy, lhc and lab ... just kidding :-)
> 
>  i still haven't worked out the math of the petals yet...
> 
> thanks again
> craig

I understand your concern about being complicated and the issue has been
raised before. I personally don't believe that if something is
complicated
that it should be avoided. I also think in the case of color many folks
"think" rgb would be complicated for a young student to understand. I
personally
think the single index method is complicated to understand because there
is no relation between color 1 and color 2 etc. Kids learn about mixing
colors to get other colors very early (before they can type). You can
think
of setpencolor [r g b] as the "color mixer".

What if setpensize 1 gave you a penwidth 1 and setpensize 2 gave you a
penwidth 10 and setpensize 3 gave you a width of 4. To me and a young
student that's about how much sense setpencolor with an index makes.
Just like
setpencolor you could train the student that setpensize 1 is 1, 2 is 10
and 3 is 4. Just like you train them that setpencolor 1 is black, 2 is
red etc.

As you suggested rgb is flexible enough to allow you to simulate an
indexed scheme and has been posted to logo-l by several folks (see
logo-l archive [link is on my web page]).

I also posted code for UCBLogo to simulate RGB but I'm not sure how it
will behave on unix (it works on DOS).

MSWLogo also allows really young students to just click on the basic
color they want from a Choose Color Dialog with sliders for Red Green
Blue
and the color they will get. It can also help teach them how RGB colors
are
mixed to achieve the color they want.

You can also add:

to red
setpencolor [255 0 0]
end

to green
setpencolor [0 255 0]
end

and so on... to the library of young students.

I also feel many Logo "experts" are not comfortable with RGB themselves
and
pass that along. RGB Should be as natural as setpensize. The setpencolor
was
done that way a long time ago when color pens on the turtle was very
limited
and even graphics terminals was limited to 16 colors if you were lucky.

It's a whole new world when you algorithmically choose color (based on
your
suggestion of CMY and LHC, I think you know that already). The most I
ever
see with setpencolor using an index is "setpencolor random x" kinda
boring
if you ask me.

The code I posted looks like a rose where it's dark in the inside and
as you come closer it changes to red, it's looks truely 3d.

-- 
===============================================================
George Mills
email: mills@softronix.com
http://www.softronix.com
The www page contains some very powerful educational software.
Our single most important investment is our kids.

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