On 26 Aug 2013, at 10:49 AM, Graham Cox wrote: > I'm working on a parser that needs to be able to extract graphics from PDF > files. So far, I'm making good headway with the CGPDFxxx functions. > > I have a question about extracting embedded bitmap images. When I encounter > an XObject stream with subType /Image, I get a bunch of parameters that looks > pretty close to the parameters to CGImageCreate. However, the 'Filter' > parameter indicates /FlateDecode so I'm assuming that I can't just wrap the > stream in a CFDataRef and then in a CFDataProvider - I'll need to actually > decompress this data first using (according to PDF spec) zlib/deflate.
As I understand it, that's correct. You may also be able to wrap the compressed data in a container such as PNG, if there's a container that can use the same compression parameters, and hand it off to CGImage for decompression (I never got around to trying this but it seems like it would work in some cases, esp. DCTDecode -> JFIF). _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
