mSetLandscapeMode switches the page between landscape and portrait orientation. Since this method changes the coordinate system of the document, your document MUST be empty when you call mSetLandscapeMode. Call mReset beforehand just to make sure.
In Windows, this method works in a very straightforward manner: call it, and the landscape mode changes.
Unfortunately, it's an entirely different story on the Macintosh. Surprisingly, the Macintosh Print Manager has NO standard way of internally setting the page orientation attribute (it's different for every printer, and not supported by any standard driver call). The ONLY safe way to change the page orientation on the Mac is by showing the Page Setup dialog and letting the user manually select landscape mode. While showing a Page Setup dialog may be fine for normal software applications such as Word, it's often uacceptable in the context of a multimedia title, especially one designed for children.
To get around this, PrintOMatic for the Macintosh relies on a "printer database" to store default landscape & portrait page setups for the most common Macintosh print drivers. This printer database consists of a set of 'PHDL' resources located in the same file as the PrintOMatic Xtra. This database is used by the mSetLandscapeMode method in the Macintosh version of PrintOMatic.
If the currently selected printer is not found in the printer database, the user is asked to MANUALLY create default Page Setups for landscape and portrait modes, and those settings are saved and added to the database. This is done through a series of prompt dialogs presented automatically by PrintOMatic when you call mSetLandscapeMode for an unknown printer.
These user-configured "custom entries" to the printer database are stored in a file called "PrintOMatic Preferences" on the user's hard disk, as well as in the Xtra file itself (if it is not on locked media). Subsequent calls to mSetLandscapeMode won't present any annoying dialogs.
What the presence of this "printer database" means is that when you change the landscape mode on the Macintosh, all the other Page Setup settings such as scaling, font substitution, etc., will also revert to those found in the entry in PrintOMatic's printer database. This is important if the user has changed any of these settings before mSetLandscapeMode is called.
If you would like to create your own "printer database" with non-standard settings, you can delete the 'PHDL' resources from the PrintOMatic Xtra document, and create your own by making calls to mSetLandscapeMode with different printer drivers selected (be sure to do them all!)