Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 4 - Printing Messages / Printing Messages Reference

Printing Messages / Universal Imaging Messages

GXImagePage

QuickDraw GX sends the GXImagePage message just prior to starting the imaging of a page. You need to override the GXImagePage message if you want to perform some task for the imaging of each page. Your override of the GXImagePage message must match the following formal declaration:

OSErr MyImagePage (gxSpoolFile aSpoolFile, long pageNumber,
                  gxFormat aFormat, void *imageData);

aSpoolFile

The file to print.

pageNumber

The page being imaged.

aFormat

The format object for the page.

imageData

A pointer to imaging-system-specific data.

function result

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

DESCRIPTION

QuickDraw GX, in its default implementation of the GXImageDocument message, sends the GXImagePage message once for each page in a spool file that is included in the count returned by the GXCountPages message.

The default implementation of this message prints the page. First, it sends the GXStartSendPage message to indicate that a page is being sent to a printer. Next, it sends the GXRenderPage message so that the imaging system can translate the page from graphics data into data for the specified printer. It then sends the GXFinishSendPage message to indicate that the page has been sent to the printer.

SPECIAL CONSIDERATIONS

You never send the GXImagePage message yourself.

You almost always forward the GXImagePage message to other message handlers. You can forward the message before or after performing your own tasks.

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 GXImageDocument message is described in the previous section.

The GXCountPages message is described on page 4-74.

The GXStartSendPage message is described on page 4-136.

The GXRenderPage message is described on page 4-96.

The GXFinishSendPage message is described on page 4-138.

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