Re: Ghostscript/GhostPDL 9.22 Release Candidate 1

[Ken Sharp]

At 11:33 19/09/2017 +0200, David Kastrup wrote:

> The question is what the complaint should be, namely what LilyPond does
> wrong.  Producing large comprehensive manuals using TeX including lots
> of example images generated using the same fonts?

Ah, you need to be careful talking about 'images' because in PDF (and 
PostScript) images are bitmaps. I don't think that's what you mean here.


> To me that sounds like a stock typesetting task with mainstream tools
> that Ghostscript should be suitable for.

Whoa, Ghostscript is a PostScript interpreter, it isn't intended as a 
typesetting application. All its really intended for is producing rendered 
bitmaps from PostScript.

It does have the pdfwrite and ps2write devices, but the intention there is 
to produce output which is visually the same as the input. There's all 
kinds of stuff you can put in an input PDF file which we don't preserve 
into the output with these devices.

Essentially its an implementation of Acrobat Distiller, with the advantage 
that it can handle a wider range of input.

And I note that the output indeed does contain the examples, in an entirely 
comprehensible way. Its simply that the output is large, and we've never 
claimed that the output won't be at least as large as the input. In fact I 
spend quite a lot of time disabusing people of that notion on Stack Overflow.


> But obviously you think there must be something wrong with the way we
> are generating and including a large amount of images into one document.
>
> Would you be willing to help us figure out a different way in which we
> could make this work?

Certainly! I did spend some time on a bug thread trying to help with moving 
away from using glyphshow. I'm happy to spend what little time I have 
explaining stuff that I know about.

However, while that covers PDF and PostScript, it doesn't cover TeX.


>   In particular Masamichi Hosoda has invested
> months of work chasing various Ghostscript versions and their
> idiosyncrasies and figuring out the best-suited TeX engines to be using
> for that task, so if there is an easy solution he and others have
> overlooked, it certainly would help having someone on board who has a
> clue about where Ghostscript is and should be heading.

Most of the idiosyncracies would, I imagine, be bugs. I'd love to say we 
could control that, but it wouldn't be true.

As to there being an easy solution, I doubt there is one. Other than using 
a tool better suited to the task of producing documentation. But that would 
almost certainly mean moving away from open source toolsets which I imagine 
wouldn't be acceptable.

Possibly not producing multiple intermediate files or not producing them as 
PDF would be an answer. From my uninformed outsider's perspective it sounds 
like you are making trouble for yourselves in this fashion, but that's 
probably a mis-interpretation.

PDF was never intended as a means of transferring, or 'containerising' 
content, its not trivial (or even possible in general) to extract content 
from, or simplify, PDF files.


> I don't see where explaining the use case for which the availability of
> the option makes much more of a difference than what you thought it
> would does amount to "berating" you.

I read the second email which simply said 'if you do this then you get a 
large file' and then listed a bunch of URLs as 'you've got to, because 
look'. I certainly didn't (and still don't) feel it explained much of the 
'use case' other than 'if you do this then its a problem'. To which my 
answer is still 'then don't do that'.

I also felt, to be honest, that the follow up was unnecessary and didn't 
add anything. Hence 'berating', possibly a poor choice of word.

Knut's email was, to my mind, much more explanatory.

I really think its time to draw this to a conclusion, as the discussion 
isn't really going anywhere. I have repeatedly said I'll discuss it 
internally. I will also say that I'm now more inclined to restore the 
behavior, though with some big warnings in the documentation.

Still, its nice to see some activity on gs-devel :-)


                    Ken