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

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"Hartmut" == Hartmut Henkel writes:

On Thu, 16 Mar 2006, Frank Küster wrote:

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Reinhard Kotucha wrote:

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<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.

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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.

No, not every ghostscript output device does antialiasing. Usually antialiasing is done for screen rendering only. And even there you can use -sDEVICE=x11 instead of x11alpha. You can try faxg3 or pcxmono or something like that.

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.

...and you don't know anything either. The question was whether files are identical, not similar. This can be achieved as I described, given that the bitmaps are produced with a reasonable high resolution (and it does not matter whether antialiasing is turned on). Of course, you have to use the same version of the program which produces the bitmaps invariably. If you want to see the differences you need a program which displays all pixels which are different in two bitmap files. But I suppose that you want to check whether two bitmaps are different before you use such a tool.

pnmpsnr: Y color component: 59.18 dB

Well, it just tells you that the files are different, the actual value does not provide any useful information. I think two tools are needed, one which tells you which pages are different and one which makes the changes visible. Regards, Reinhard -- ---------------------------------------------------------------------------- Reinhard Kotucha Phone: +49-511-4592165 Marschnerstr. 25 D-30167 Hannover mailto:reinhard.kotucha@web.de ---------------------------------------------------------------------------- Microsoft isn't the answer. Microsoft is the question, and the answer is NO. ----------------------------------------------------------------------------