Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 4 - Printing Messages / Printing Messages Reference

Printing Messages / PostScript Imaging Messages

GXPostScriptSelectPaperType

QuickDraw GX sends the GXPostScriptSelectPaperType message prior to imaging the page, to select the printer's paper type for the page. You can override the GXPostScriptSelectPaperType message to do anything you need to do to make sure the device is set up correctly. Your override of the GXPostScriptSelectPaperType message must match the following formal declaration:

OSErr MyPostScriptSelectPaperType (gxPaperType aPaperType,
         long pageIndex, gxPostScriptImageDataHandle hImageData);

aPaperType

The paper-type object that is needed.

pageIndex

The page number of the page that is about to be imaged.

hImageData

A handle to the PostScript imaging system structure.

function result

An error code. The value noErr indicates that the operation was successful.

DESCRIPTION

The PostScript generic driver invokes the GXPostScriptSelectPaperType message when it is setting up the format for a page--after the page has been despooled but before it is imaged. This message selects the paper type for a printer. This message is sent by the default implementation of the GXPostScriptDoPageSetup message.

The default implementation of this message looks for a collection item of type 'post'
in the paper-type collection and sends that to the printer as the paper type for the page. The collection item must be valid PostScript that works for all PostScript devices.

You can override this message to customize the way that setting the paper type for the page works.

SPECIAL CONSIDERATIONS

You usually forward the GXPostScriptSelectPaperType message to other message handlers; however, if you are overriding this message to issue your own setpagedevice operation, do not forward this message.

RESULT CODES

gxSegmentLoadFailedErr	A required code segment could not be found, or there was not enough memory to load it.
gxPrUserAbortErr	The user has canceled printing.
gxPaperTypeNotFound	The specified paper type could not be found.
gxNoSuchPTGroup	The specified paper type could not be found.

The default implementation of the GXPostScriptSelectPaperType message can also return the communications errors that are listed in Table 4-2 on page 4-42.

SEE ALSO

The PostScript imaging system structure is described on page 4-26.

Paper types and paper-type collection items are described in Inside Macintosh: QuickDraw GX Printing.

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