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Re: Examples of use of svg.el?
From: |
Eduardo Ochs |
Subject: |
Re: Examples of use of svg.el? |
Date: |
Fri, 1 Apr 2022 21:12:38 -0300 |
On Fri, 1 Apr 2022 at 18:47, Michael Heerdegen <michael_heerdegen@web.de> wrote:
>
> Eduardo Ochs <eduardoochs@gmail.com> writes:
>
> > Hi list,
> >
> > I am trying to learn how to use svg.el, and I plan to use it mainly to
> > plot mathematical functions.
>
> Why don't you want to use Calc?
>
> Michael.
Hi Michael,
I don't have a short answer for that, but I'll try to make my longish
answer short enough...
There are some programs that most people find very easy and a few
people find very hard. My favorite example of that is Org, see:
http://angg.twu.net/2021-org-for-non-users.html
A quote:
"At some point in 2021 I finally understood why I have always found
Org Mode so hard to use. To make a long story short, I am a very bad
_user_: when I try to use something and I can't make a clear mental
model of what's going on my first reaction is to try to look at the
data structures and at the source code - and the code that
implements code blocks in Org is hard to understand."
I was never able to learn Calc properly, and I _guess_ that the main
reason for that is because I've never found a good way to record my
interactions with Calc and "play them back" later.
Take a look at the first three screenshots in:
http://angg.twu.net/2022eev-svg.html
The third screenshot shows a quadratic function. I know how to make
Maxima draw something very similar to that; Maxima generates a script
for gnuplot, and asks gnuplot to render it. The script can be saved to
a file, and I learned a lot about gnuplot by examining these scripts.
I only learned that Calc can do graphics via gnuplot a few minutes
ago:
(info "(calc)Graphics")
The quadratic function in my third screenshot is defined in this way:
x0 = 3
y0 = 2
z = z(x,y) = (x-x0)^2 - (y-y0)^2 + 2
How would you make Calc plot it for x in [x0-1,x0+1] and y in
[y0-1,y0+1]? Also: how do we access the script that Calc sends to
gnuplot?
Btw, my way to script my interactions with Maxima is demo-ed here:
http://angg.twu.net/eev-find-angg.html
The third thumbnail - the one that shows a 3D plot - points to this,
http://www.youtube.com/watch?v=FoAzpGzFCSE&t=15m14s
that nowadays is one of my favorite short demos of eev in action - as
in: "hey, if you've never seen how to use eev to control REPLs then
follow this link and watch 30 seconds of the video... note that the
`&t=15m14s' make Youtube start playing it from 15:14".
I would _really_ love to make something similar for Calc. Any help
would be greatly appreciated!
Cheers & thanks in advance,
Eduardo Ochs
http://angg.twu.net/#eev