[Magick-bugs] irreversible convert to pdf

[Maciej Pilichowski]

Hello,

  First of all -- thank you very much for a great set of tools. I 
didn't even "bite" all of the tools and I already enjoy it.

  One problem, and I believe a bug, though -- I assume convert should 
be a reversible process when talking about lossless formats. However 
when I can convert .png to .pdf I get 1:1 conversion, no loss, but 
when I convert it back (from this converted file), i.e. from .pdf 
to .png I get the same size of the image as the original .png file 
but whole content (not-white pixels) are placed in lower, left 
quarter of the image (it is scaled down). So at this point convertion 
does not keep the quality of the image.

  On another test I convert .pdf (which was converted from .jpg) 
to .png. As above, I would expect no quality loss because .png is 
lossless, but now I get a bit smaller image (size, width and height) 
and much poorer quality (it almost looks like the convert used .jpg 
as the middle layer, i.e. pdf -> jpg -> png).

  I run convert in minimum form, like:
  convert file.png file.pdf

  System: opensuse 10.3, imagemagick 6.4.3.6-7.1.

  Please let me know if I could be more helpful investigating this 
issue.

Kind regards,