corrupt image when using -gaussian with PNM files

[RetroJ]

I was able to reproduce this bug on http://jjfoerch.com/bitbucket/cookie.jpg

This works fine:

Code: Select all

convert cookie.jpg new.pnm

This produces a corrupt image:

Code: Select all

convert cookie.jpg -gaussian 1x1 new-blurred.pnm

Using Imagemagick 6.3.1 01/10/07 Q16 on Debian.

[magick]

A 16-bit PNM is valid. However, kview and gimp may not support anything beyond 8-bits. Try this command:

• convert original.pnm -gaussian 1x1 -depth 8 result.pnm

to create an 8-bit PNM image.

[anthony]

technically the depth for all but bitmap NetPBM images formats (whcih includes PNM whcih is a suffix fro ANY NetPBM format without being specific) can use any maximum value from 1 to what ever your INT maximum is for your machine!

I myself use some very odd depths when using the format to create specific images.
For examples see Resized gradients...
http://www.cit.gu.edu.au/~anthony/graph ... ent_resize

[RetroJ]

Very interesting. Nice to see that ImageMagick is not at fault here, and indeed, has a feature that those other programs lack.