[NTG-pdftex] Creating identical PDF files with different pdfTeX runs

[Frank Küster]

Hartmut Henkel <hartmut_henkel at gmx.de> wrote:

> On Thu, 16 Mar 2006, Frank Küster wrote:
>
>> Reinhard Kotucha <reinhard.kotucha at web.de> wrote:
>> >
>> > <pagenumber> <md5sum of the bitmap file>
>> >
>> > The bitmap files can be removed by the script when it is finished and
>> > standard UNIX tools can be used to examine the output files.
>> >
>> > Particularly, diff(1) can be used efficiently.  It will tell you the
>> > numbers of the pages which are different.
>>
>> That's a very good suggestion, thanks!
>
> this looks pretty fragile to me. Characters will end up in bitmaps with
> interpolated gray pixels, and so it depends not only on pdftex but also
> on any subtlety of the rendering engine. And if the md5sum doesn't
> match, you know nothing without the original file. 

Yes, we definitely need the original file.

> Maybe some
> crosscorrelation between images with some given tolerance limit would be
> safer.

Any hints what I could use for such a purpose?  

Regards, Frank
-- 
Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX)