BTW, can we assume that you really have Form XObjects in your PDFs? That
question is still open.
According to the PDFTron code it never enters a Form XObject, it goes
straight into a Path Object.
For example:
I actually managed to get an answer from Adobe about how they export images.
First I should say that Acrobat has an "Export All Images" functionality
that only exports raster images. What I am using is the "Save As HTML"
functionality that exports all images including the vector graphics but
converts them to bitmaps. According to Leonard Rosenthol
(http://www.acrobatusers.com/blogs/leonardr) when Acrobat comes across some
path data that is not tagged or in Form XObject they group the data into
"areas" according to some algorithm.
Seeing these final images separated like this is what made me think that my
vector graphics were grouped inside the content stream somehow and my
failing attempts to retrieve it like so was at no fault to PDFBox or any
other Java PDF Library.
Still your help is greatly appreciated,
Graeme