[pdftex] pdftex compression -- proposed addition to manual

Hans Hagen pragma at wxs.nl
Tue Aug 21 11:56:57 CEST 2001

At 01:03 PM 8/20/2001 -0700, Ben Crowell wrote:
>  Thanks, Siep Kroonenberg, for your comments! I took the liberty
>  of incorporating them more or less verbatim into the proposed
>  addition to the manual. Is this OK with you?
>  However, this just makes me wish more for an answer to the question
>  I previously posed about what pdflatex actually does with PNG
>  images, since, AFAICT from the Adobe docs, PNG can't be incorporated
>  in PDF without converting to some other format such as JPEG, CCITT,...

it's not so much inclusion as well as compression and the way the stream is 
organized that is of importance here

as far as i know [which is not that much] png en tiff are related to 
lossless zip/lzw compression [predictors] while jpeg is a lossy compression 
scheme; so, pdftex has to convert to these, which in case of png/jpeg input 
is less complicated since they can be kind of passed on, while tiff input 
[there are many kind of tiffs] must be converted. In principle more input 
formats could be supported, in which case for instance bmp could end up zip 
compressed with png predictors.

                                   Hans Hagen | PRAGMA ADE | pragma at wxs.nl
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