Transparency layers in pdf

[Jochen Grefe]

Hello everybody,

I have a polygon layer with TRANSPARENCY 50 that lay on top over
a raster layer. While it renders as expected to png the polygon
are opaque when renderd to pdf. Despite using FORMATOPTION
"OUTPUT_TYPE=RASTER"
or not.

The raster layers are rendered internally to jpeg because of the
absence of inmemory opening of png images in former pdflib versions.
Since the newest library (6.01, I don't know until wich version it worked)
supports this, I tested the rendering to pdf over png. Which give me a lot
of better quality as the jpeg pdf but don't helped me with the transpareny
issue.

Any help is appreciated,
jochen