Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 4 - Printing Messages / Printing Messages Reference

Printing Messages / Spooling Messages

GXSpoolPage

QuickDraw GX sends the GXSpoolPage message when a page is ready to be sent to the spool file. You can override the GXSpoolPage message to change or add to a page being sent to a spool file. Your override of the GXSpoolPage message must match the following formal declaration:

OSErr MySpoolPage (gxSpoolFile aSpoolFile, gxFormat aFormat, 
                  gxShape aShape);

aSpoolFile

The file to which the page is being written.

aFormat

The format that goes with the page.

aShape

The data that belongs on the page in the form of a picture shape.

function result

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

DESCRIPTION

QuickDraw GX sends the GXSpoolPage message when an application calls either the GXFinishPage function or the GXPrintPage function. This message takes a picture shape in the aShape parameter that represents a page and writes it to the spool file referenced by the aSpoolFile parameter.

You override this message when you need to perform any per-page operations such as adding data (for example, a background picture or confidential stamp) to each page. You need to change the page before forwarding this message because the page is written to the file before control returns from the forwarded message.

The default implementation of GXSpoolPage writes the data into the spool file in a standard format.

SPECIAL CONSIDERATIONS

You rarely send the GXSpoolPage message yourself.

If you are providing your own spooling, you need to totally override GXSpoolPage and all of the other spooling and despooling messages.

If you are not providing your own spooling, you must forward this message to allow the default implementation to write the data into the spool file.

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.

SEE ALSO

The GXFinishPage and GXPrintPage functions are described in Inside Macintosh: QuickDraw GX Printing.

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