[softwarelist] Re: pdf import

In message <346f53a94e.arnold@arnold.>
          Arnold van der Heijden <info@xxxxxxxxx> wrote:

> In mailtje <AbzMwcCHrLtFFwWB@xxxxxxxxxxxxxxxxxxx> schreef je:
>
>> My interpretation would be that the problem is that the JPEG data is
>> turned into a bitmap in PostScript, the loss of compression and the
>> inefficient way that PostScript uses to save files leading to the
>> increase.
> 
> Yes, but also a simple line of text makes from a 7 kb pdf-file
> a about 900 kb Ovation-document. So, it's not only the bitmap
> in the postcript.

The size increase you see here could just be the preview bitmap in 
OvationPro. The size of the preview bitmap is not directly related to 
the file size of the PDF file (only to the page size).

However, it is not just that. I have experimented with a simple PDF 
file containing a line of text and a coloured background rectangle and 
found out something interesting about Ghostscript's epswrite device: 
It rasterized the text and therefore the resulting output size depends 
on the resolution parameter that was specificed. The text was in a 
Type1 font referenced by name ("Helvetica"), so that should be the one 
thing one could have expected to never be rasterized, so if even that 
is rasterized, it probably applies to all other text, too.

The size increase with JPEGs is a different matter though. It appears 
that the Ghostscript epswrite device always uncompresses JPEGs and 
stores them as uncompressed bitmaps in the EPS. This is independent of 
the chosen output resolution, i.e., the image is not resampled, just 
uncompressed. It is beyond me why the epswrite device would want to do 
that though - the output is labelled as LanguageLevel 2, which could 
retain the original JPEG data.

So, to sum it up: I do not think the epswrite device is really 
suitable for that kind of task.

Martin
-- 
---------------------------------------------------------------------
Martin Wuerthner          MW Software          martin@xxxxxxxxxxxxxxx
---------------------------------------------------------------------

Other related posts: