[GRLUG] Illustrator PDFs

[Grand Rapids Linux Users Group]

On 3/6/21 7:39 AM, Grand Rapids Linux Users Group wrote:
> On Fri, 2021-03-05 at 17:42 -0500, Grand Rapids Linux Users Group
> wrote:
>> Yeah, I had to use it for something, and had to manually download it
>> and install some older libraries to get it to work.
>> Also, it doesn't matter what created the PDF - PDF is PDF.
> Well, sort of.  If it is a font issue what you have is a font mapping
> issue.  You need to change the font map or install the matching fonts.
>
> This isn't a Linux issue, not really.   I process thousands a PDF a day
> which get sent all over the world and fonts go kittywhumpus if they
> fontmap is bad.
>
> See the feature "scrubbrush" in the workflow engine I maintain for an
> example.
> http://www.opengroupware.us/pdf-scrubbrush
>
> Something like "/usr/bin/pdftocairo  -pdf -origpagesizes input.pdf
> output.pdf" may 'fix' the PDF.
>
> If the PDF uses truly exotic fonts... you are pretty much screwed.
>

To expand on this, the format of PDF fonts is very well defined. It's 
just that the details of the specification are so far reaching that it's 
difficult to build an implementation which covers all of the edge cases 
and fallbacks.  It's right out in the open how it's supposed to work.  
But in my experience, almost nobody actually uses all of the edge cases 
all the time, so stuff gets untested from one software release to 
another.  It's akin to something like "Your job is to write a PNG image 
editor.  Here's the specification for a PNG image file.  Pretty simple.  
Except sometimes it contains a block of HTML and CSS3 you need to 
overlay on it.  Here's the specification for that.  And you're the first 
one to write an open source HTML renderer.  Oh, and it needs to support 
everything from the broken IE6 box model to CSS3 animations and 
transitions for some reason."  PDF is not a terribly complicated 
format.  Except for fonts and some of the weirder forms of raster image 
data.  There be dragons in those chunks of the spec.

Warm Regards,
Kyle Maas