[texhax] Transparency via \includegraphics?

[Reinhard Kotucha]

>>>>> "Pavel" == Pavel Minev Penev <pavpen at berkeley.edu> writes:

    > I guess you are using PDFLaTeX and the graphicx package does not
    > properly preserve transparency when converting PNG to PDF.  You
    > can either try to modify the graphicx package, or find an
    > appropriate external PNG->PDF/PS converter that does not replace
    > transparent pixels by pixels of a certain color.  Unfortunately,
    > neither the netpbm package, nor ImageMagick, nor GIMP seem to do
    > what you need.

The graphics package does not convert anything.

pdftex does not convert PNG to PDF because PDF viewers understand
PNG.  pdftex just puts a wrapper around the graphic which contains
some information about the size and resolution.

I doubt that transparency in PNG files is supported at all in PDF.

But you can try:  If you insert a PNG file, which behaves as expected
in some web browser, into a TeX document and it does not appear
properly in Acroread 6, than it is quite likely that transparency is
not supported for PNG files.

I did not find anything about this in the PDF Reference Manual.

Transparency is supported for vector graphics.  I remember that Hans
Hagen demonstrated this at a TeX conference some time ago.  He didn't
use PNG (bitmaps).  The graphics had been produced by metapost.

Maybe it is better to ask questions like this on the pdftex mailing
list.  There are the experts.

Regards,
  Reinhard

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