Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 4 - Printing Messages / Printing Messages Reference

Printing Messages / PostScript Imaging Messages

GXPostScriptDoDocumentHeader

QuickDraw GX sends the GXPostScriptDoDocumentHeader message to generate the PostScript program header for a document. You can override the GXPostScriptDoDocumentHeader message to change the PostScript document structure and formatting setup for a document. Your override of the GXPostScriptDoDocumentHeader message must match the following formal declaration:

OSErr MyPostScriptDoDocumentHeader (
                        gxPostScriptImageDataHandle hImageData);

hImageData

A handle to the PostScript imaging system structure.

function result

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

DESCRIPTION

QuickDraw GX sends the GXPostScriptDoDocumentHeader message during its default implementation of the GXImageDocument message when printing to a PostScript device. The GXPostScriptDoDocumentHeader message is the first message sent when generating a PostScript program. QuickDraw GX uses this message to generate a PostScript program header, which is required for conforming PostScript programs. The information for the header is obtained from the job object.

You can override this message to build your own document header or to add comments to a PostScript header.

SPECIAL CONSIDERATIONS

You can totally override the GXPostScriptDoDocumentHeader message to build your own PostScript program header, or you can forward this message and then add your own information to the header created by the default implementation.

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.

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

SEE ALSO

The GXImageDocument message is described on page 4-93.

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

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