POV-Ray : Newsgroups : povray.pov4.discussion.general : On povr's accidental text{cmap} capability. : Re: On povr's accidental text{cmap} capability. Server Time
24 Feb 2024 16:23:34 EST (-0500)
  Re: On povr's accidental text{cmap} capability.  
From: Bald Eagle
Date: 1 Apr 2023 10:45:00
Message: <web.6428431f1ce613a61f9dae3025979125@news.povray.org>
William F Pokorny <ano### [at] anonymousorg> wrote:
> I admit to not paying attention to 'cmap' when it was being worked on in
> early 2019. I wrongly thought it was freetype fork specific and I tuned
> it out while busy with other code play.

I was going to point you to that thread, but I had figured you knew about it.
(oops)

> ---
> Aside: For a short time saw a very strange parsing error more text{}
> related than cmap{}. I started with some example cmap{} code off the
> newsgroup and it initially failed. It seemed somehow related to a
> semicolon following the string declare used within the text{} object!
> The SDL declare looked like:
>
> #declare MyText = "..."; // Semicolon not needed.
>
> However, as I played the parsing error went away and, try as I might,
> I've been unable to reproduce that parsing fail. Maybe something like
> dos line terminations vs unix/linux ones - or some utf8 character
> elsewhere in the scene mangling things. I don't know. Still, for the
> record, I did see what looked to me to be a bogus parsing fail while
> working on a scene with cmap{}.

Have you tried sorting out that diacritical mark issue we were having a while
back?   That seemed really strange.  Had to solve it by using a totally
different font file.

Also, I have been getting some weird parse errors, for reasons that don't make
sense.

Perhaps they are due to my structuring of the code, but I feel that they are
just too weird - and - from a user perspective - unexpected behaviour.

Over the years, I also notice instances of transient and unreproducible
behaviour in scenes that DO parse and render successfully.
There are definitely ghosts lurking in the machine's code.  I suppose that I was
always uneasy about trying to point them out as possibly being real, since I'm
not a professional programmer, and POV-Ray has always had it's unique issues.  I
guess I just felt like it would get trivialized and dismissed, and I would have
a hard time supplying a scene that demonstrated the error or strange behaviour.
(just look at your recent dictionary / core dump experiments)

I will try to note and document such things more diligently in the future.

At present, I have 2 issues in the same scene/inc pair, that I sent to jr for
inspection.  I have also spent the last week chasing my tail around in circles
trying to sort out the vertices and edges of these triangles.  In my development
scene, it appears that I have everything working the way I want to and expect.
When I switch over to rendering all of the patterns, two that are not radially
symmetric are rotated - even though my preliminary debugging suggests that it
doesn't make any logical sense.

Given that you are presently in the thick of unraveling all of the keywords that
have different scopes and meaning, and we know that we have 2 different parsers
and different solvers, and ....   I would encourage others to post their
experiences in debugging their own scenes, as this would not only help spot
potential real issues, but also serve to show where SDL and/or its documentation
perhaps isn't clear enough, and revising things in those areas would be time
well spent.

- BW


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