[Jmol-users] png files created in jsmol

[João P. M. <joa...@gm...>]

Hello!

I use jmol inside SageMath which I build from source. Currently this is 
Sage 7.6 which comes with  jmol-14.6.1_2016.07.11 from which it uses 
jsmol. When producing a 3d graphic one has the option of saving or 
exporting files in various formats from a context menu. One of them is 
PNG files, namely "export PNG image". The files produced in this manner 
fail to pass testing with the pngcheck utility. Opening the file with 
gimp and exporting to png format one ends up with a smaller file without 
apparent image quality loss which is considered OK by pngcheck. Is this 
intended behavior and the file getting some extra information, or some bug?

Typical output of pngcheck in one of these files:

pngcheck Fromjmol.png
Fromjmol.png  additional data after IEND chunk
ERROR: Fromjmol.png

The file in question is available at:

https://drive.google.com/file/d/0BxvQu5VZ1xbeODl6R01aMVJSeFE/view?usp=sharing 


I believe jmol is not particularly changed by sage and this probably the 
best place to ask the question. Sorry, if this not the case.

Best, and thanks for Jmol,

João Palhoto Matos