[pdftex] Best bitmap image format?

[Reinhard Kotucha]

>>>>> "Robin" == Robin Fairbairns <Robin.Fairbairns at cl.cam.ac.uk> writes:

  > hans h writes:
  >> Olivier Lefevre wrote: > I must embed application snapshots in a
  >> document. Which format will > work best as far as pdftex is
  >> concerned? The snapshot tool can save in > all the usual bitmap
  >> formats (e.g., gif, png, jpeg) and also as eps > and pdf but for
  >> a bitmap image that is not very natural.
  >> 
  >> black and white bitmap : png color bitmap : jpg vector : pdf
  >> metapost : mps

  > why do you suggest a "colour bitmap" should be represented using
  > jpeg?  -- for screen shots it seems a really unfortunate choice.

  > as martin did, i too would recommend png for this application;
  > though i do regularly use jpeg for photos (which is what it was
  > designed for, i believe).

I agree with everything you said and I also recommend to use PNG for
screenshots.  However, someone on this list reported that his
publisher required CMYK colors in included graphics which is not
supported by PNG.  Maybe Hans had this in mind.

JPEG compression works very well if a pixel does not differ very much
from adjacent pixels.  This is the case for photographs, television
and audio.

Bad results are to be expected with line graphics or screenshots where
one pixel is white and an adjacent pixel is black.

PNG is the first choice for anything created by a computer, i.e. files
produced by Metapost, Gnuplot,... or screenshots.  Files produced by
ray tracers have similar properties as photographs and JPEG
compression might be applicable.

Though I agree with George that in many cases some tweaking is
necessary, I recommend to simply convert the screenshots to PNG and
check whether the result is acceptable.  I suppose that it is in most
cases.

And it's worth to try

    http://www.inf.bme.hu/~pts/sam2p

Regards,
  Reinhard
 
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