[OS X TeX] graphic conversion

[Peder Axensten]

On 14 feb 2005, at 18.13, Chris Goedde wrote:

> On Feb 12, 2005, at 3:07 AM, Denis Chabot wrote:
>
>> I still find it amazing that there would be no converter from pdf to 
>> pict that could preserve vector objects. Maybe I'll fire back old 
>> Classic, where QuickDraw is the native engine, and see what I can 
>> get.
>
> I agree this is frustrating, but it's not so surprising if you think 
> about what pdf (and its ancestor, postscript) are: they are output 
> formats, not document exchange formats. A pdf document is really a 
> program for drawing marks on a surface (real or virtual) that needs to 
> be interpreted. There aren't really that many independent interpreters 
> on the planet, and most are focused on rasterization (i.e. actually 
> running the program) rather than translation (rewriting the program in 
> a new language). The translation of pdf <---> eps is fairly 
> straightforward because of their close relationship, but translating 
> pdf to pict is probably a very different story (I know nothing about 
> the pict format) due to differing models/capabilities of the pdf and 
> pict languages.

I'm under the impression that the difference between pdf and eps is 
that pdf has NO "programming", whereas eps and ps have. The conversion 
between ps and eps is extremely straightforward and can often be done 
manually with a text editor. But to convert them to a pdf you need to 
render the code and this is not straightforward, you need Distiller or 
Ghostscript to do it. This is why pstricks doesn't in pdflatex without 
extra steps to render the resulting ps code.

> One might think that it would be possible to just pick out the 
> important bits of the pdf file without interpreting the whole thing, 
> but due to the power and flexibility of pdf, this is not really 
> possible. For example, in pdf (and postscript), it's possible to 
> change the coordinate system in fairly arbitrary ways (scale, 
> translate, rotate, skew), so a chunk of code that at first glance 
> looks like a circle or a square may actually represent an ellipse or a 
> rhombus.
>
> So, the current situation is unfortunate and frustrating, but not 
> entirely surprising.
>
> -- 
> Chris Goedde
>
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/Peder
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Mac-TeX Website: http://www.esm.psu.edu/mac-tex/
           & FAQ: http://latex.yauh.de/faq/
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