Pictures are drawn in presentation spaces associated with device contexts. PM considers a metafile to be an output device or destination, in the same manner as a window or printer. This means that to record a picture in a metafile, a metafile device context must be created and associated with a presentation space.
A metafile device context is created by calling DevOpenDC and specifying the type of device context as:
OD_METAFILE is generally used to specify a metafile device context, although OD_METAFILE_NOQUERY provides better recording performance. OD_METAFILE_NOQUERY does not support attribute queries, for example, GpiQueryCurrentPosition, or GpiQueryColor.
The device driver for the device that the metafile device context is associated with is specified in the DEVOPENSTRUC data structure required for DevOpenDC. DEVOPENSTRUC is described in Print Job Submission and Manipulation.
A metafile device context can be associated with a newly-created presentation space by calling GpiCreatePS and specifying the handle to the metafile device context returned from the call to DevOpenDC. A metafile device context can also be associated with an existing, normal presentation space by calling GpiAssociate and specifying the handle to the metafile device context returned from the call to DevOpenDC.