[pdftex] Re: Best bitmap image format?

Olivier Lefevre lefevrol at yahoo.com
Mon Feb 27 06:29:32 CET 2006


> ah, so application snapshots are screen dumps ...

Yes indeed, sorry if that was not clear but then the only other meaning 
of "snapshot" I know of is dump of the memory image of an entire 
application to disk (lisp-like) and that has nothing to do with images.

So, trying to recapitulate, for a PDF destined to be viewed, a 
simplistic (s)RGB PNG should be fine (esp. as we want to keep the file 
small) but I may need to redo all the snapshots if ever we want a 
printed version done by a print shop, correct? What I still don't 
understand is which image formats are native to PDF and pdftex: 
apparently only JPEG, right? How are images stored inside a PDF?

Also, keep in mind that for this technical manual color accuracy is 
hardly a top priority, as the colors are completely arbitrary anyway and 
carry no meaning. I'm more concerned with avoiding blurry images.

That leaves the issue of whether I should do the PNG -> PDF conversion 
myself or leave it up to pdftex. Opinions seem to diverge on this issue.

 > if you look closely at your screen shots, you will see a lot of funny
 > colors around text that are probably due to clear-type anti-aliasing
 > (did you use an LCD display?).

Yes I am using ClearType even though this is a CRT. The difference is 
remarkable: I no longer get headaches. I don't think I will need to turn 
off ClearType because this is a Java app we are talking about and it 
does it own rendering but I will keep an eye on it; thanks for pointing 
it out.

 > You should avoid anti-aliasing in the display used for screen dumps
 > and hope that the PDF rasterizer supplies anti-aliasing when the
 > documents are viewed.

Not likely: did you ever try viewing a PDF with bitmapped fonts inside 
Acrobat? Simply awful.

-- O.L.



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