will be set a sinkflag_topdown flag can be set to indicate the source 39 s preference to supply data in a top down order while a sinkflag_bottomup flag can be set to indicate the source 39 s preference to supply data in a bottom up order other flags include a sinkflag_fullwidth flag which indicates whether the source prefers to supply data in bands and a sinkflag_multipass flag which indicates whether the source prefers to supply data in multiple passes if the source wants to composite the data of interest over data already existing in the sink a sinkflag_composite flag may be set upon successful return from the beginsink method the sink fills the imageinfo structure which the source may then access completing the negotiation between source and sink in most cases in particular the sink should fill out rawdataformat with the file format id if the sink can take raw image data in that format in this case the source then calls the pushrawdata method to pass raw image data to the sink if the sink cannot take raw image data from the source it fills out rawdataformat with imgfmt_memorybmp in which case the source calls pushpixeldata or get releasepixeldatabuffer as described below the sink should fill pixelformat with the pixel format preferred by the sink this may be the natural pixel format for the.