The printing margins in mozilla are not adjusted from their default of 0.5 inches on the Mac. They should be calculated from the PMPageFormat record (page setup info).

Conrad Carlen: Do you mean that MacOSX's print API has methods to query the margin sizes for a specific printer (if "yes" we may hook-up a common API for all platforms since at least Xprint on Unix/Linux has a similar feature...).

Yes. The Carbon Printing Mgr has: PMGetAdjustedPageRect - Obtains the page size, taking into account orientation, application drawing resolution, and scaling settings. PMGetAdjustedPaperRect - Obtains the paper size, taking into account orientation, application drawing resolution, and scaling settings. PMGetUnadjustedPageRect - Obtains the size of the imageable area in points, unaffected by orientation, resolution, or scaling. PMGetUnadjustedPaperRect - Obtains a rectangle that specifies the size of the paper in points, unaffected by rotation, resolution, or scaling. The difference in the "page" rect and the "paper" rect gives us the margins. I'm not sure if it's needed to determine this for a specific printer. These routines pertain to the printer chosen for the current job which is all we need, right? Currently, all we ever use is PMGetAdjustedPageRect, which is why our margins are too big on OS X - they're the physical margin + 0.5 inch.