Q: We need to do some preflighting and are not sure if there is a
function in PDFTron to determine the resolution or Dots Per Inch (DPI)
of a PDF document?
If there is a getDPI() function does this apply to the entire document
in one call or do we need to examine each and every element within a
PDF. For example if a document ahs 3 JPGs and 1 Tiff can we get the
DPI of those elements and do we need to get element by element by
enumerating all the elements within a PDF and examine the listed
items?
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A: You would need to check every image element in a document (using
ElementReader).
Given an image element you can obtain its approximate resolution on a
PDF page as shown in the following article (http://groups.google.com/
group/pdfnet-sdk/browse_thread/thread/
eefd5c8373c19608/0962ad14c0fd30f8 or search for "image resolution" in
http://groups.google.com/group/pdfnet-sdk).