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

On Thu, 16 Mar 2006, Frank Küster wrote:

Reinhard Kotucha 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. Maybe some crosscorrelation between images with some given tolerance limit would be safer. Regards, Hartmut