Jeremias Maerki schrieb: > AFAIK, BDC/EMC (since PDF 1.2) are defined my the "Marked Content" > chapter in the spec and are used primarily for identifying certain marks > on a page. They are the basis for Tagged PDF. But they don't have an > influence on the rendering. I've worked on that in FOP recently so I > know a few things here. > > "Optional Content" has been introduced with PDF 1.5. It is used mainly > for group content together, ex. layers in Illustrator. I haven't looked > at OCG closely, yet, but they allow to show and hide certain marks > (content groups). > > Anyway, if your test files render badly, I don't think it has to do with > these features. If I understand this stuff correctly, the above is > mainly about switching on and off the rendering of certain marks. If you > like I can take a look at your test files that don't work properly and > try to have a look myself. Maybe I can give you a hint where to look. Perhaps it might be useful to have a look at the implementation of the clipping operators. Some rendering of pdfs is improved but some are getting worse, e.g. have a look at the flyer.pdf attached to PDFBOX-358. Without clipping is looks quite perfect, but after enabling it some of the content disappears or isn't rendered correct. Perhaps it is a problem with the direction of the path and the winding rule which describes in the end what area is painted or not??
Andreas Lehmkühler > On 01.05.2009 00:55:15 Daniel Wilson wrote: >> Some of my stencil-masked documents are still rendering badly. >> >> The only operators they use that are not implemented are the BDC and EMC >> operators -- the marked-content sequence begin and end operators (section >> 10.5). These are briefly discussed relative to XObjects as "Optional >> Content" in section 4.10.3. >> >> I'm sure these things have some significance, but are they significant to >> rendering a flat image -- PNG, JPG, etc. ? Or should I be looking elsewhere >> for the outstanding problems? >> >> Thanks once again for your thoughts! >> >> Daniel Wilson > > > > > Jeremias Maerki >
