Technical Q&A QD54

Setting Landscape Printing from an Application

Q: How can I set landscape mode printing from within my application?

A: Apple has always cautioned applications against trying to force landscape printing on the user; however, there are certain apps in the marketplace that have good reason to do this. Therefore, even though there is no API in "classic" printing to set landscape mode, here is an overview of a method that you may want to consider implementing if you need to force the orientation of your print job:

1. Call PrValidate on your print record to ensure that the contents of your print record are compatible with the current active printer driver.
2. Look at the values of the paper rectangle in the print record. If it is wider than it is tall, your user has already selected landscape mode. If it is taller than it is wide, then you need to put up an alert asking your user to choose landscape printing, followed by a call to PrStlDialog so they can set the orientation.
3. Call PrValidate again to ensure that the user did change to landscape mode. If the paper rectangle is still taller than wide, go back to step 2 and ask the user to set the orientation again because they did not follow or did not understand the instructions in step 2.
4. Save the print record with the correct orientation in the resource fork of the preferences file, and read it back in each time the user needs to print. For information on how to save print records, refer to the Premier Issue of develop 1990, page 58. By saving and using the saved print record, the user is only bothered by the PrStlDialog *once*. Thereafter, the print record is restored from preferences when printing needs to occur.
5. If the user changes printer drivers in the Chooser, the call to PrValidate will fail, and PrDefault must be called. This will make a new print record for the new printer driver, and it will default to portrait mode (not landscape mode), so, go back to step 2.