[pdftex] User Comments

[Hans Hagen]

Ross Moore wrote:

> This is a known "feature" in Ghostscript.
> For some time now it has had some  auto-rotate  coding that seems to  
> be used
> by default.
>
> There are various ways to turn this off;  e.g. by including the switch
>    -dAutoRotatePages=/None
> within the command to call  gs  (i.e. Ghostscript) in whatever script
> or batch-command you are using.

indeed; when converting eps file, it makes sense to take a look at the 
documentation that comes with gs, it mentions a whole lot of such 
variables (downsampling, color spaces etc) and for high end pruduction 
one should set some of them

>
> There are several different kinds of Box (e.g. /MediaBox , /ArtBox , / 
> CropBox ,
> etc.) that can be specified for a PDF document, such as a single image.
> When a file is converted from .eps or .ps it is not always clear  
> which of these,
> if any, will be set with the  %%BoundingBox  info.
>  pdfTeX  just includes the graphic, using whatever Box information  it 
> finds.
> When that information is actually not reliable, you can see bad results
> and wrongfully attribute it to  pdfTeX  rather than to an earlier  
> process.
>
pdftex can choose what box to take and there is no clear rule on this 
since graphic programs (& designers) are not consistent in this; for 
older graphics you need the media or cropbox, for newer ones, the artbox 
may be the one ti set, but don't be surprised to find illustrator files 
with completely off page (outside graphics bbox)  artboxes which would 
then render emptyness. Also, sometimes boundingboxes are uses to achieve 
special effexts (tight box with bleeding graphics) in which case 
cropping is not-done; often these boxes have to be chosen/applied on a 
per-designer, per-application, per-version-of-application basis

btw, older versions of ghostscript had problems with negative 
coordinates (actually, in practice the negative coordinates were not the 
problem, since in the case at hand they were the result of bugs in 
drawing programs)

some info can be found in:  
http://www.pragma-ade.com/general/technotes/pdfboxes.pdf

Hans

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