GXCreateImageFile(IM:XP)

Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 4 - Printing Messages / Printing Messages Reference

Printing Messages / Universal Imaging Messages

GXCreateImageFile
QuickDraw GX sends the GXCreateImageFile message before the imaging of a print job begins. You need to override the GXCreateImageFile message if your device requires that an image file be created. Your override of the GXCreateImageFile message must match the following formal declaration:
OSErr MyCreateImageFile (FSSpecPtr aFSSpecPtr, 
                        long imageFileOptions, 
                        long *fileReference);
aFSSpecPtr
Where to create the image file.
imageFileOptions
Options for creation of the image file, as shown in Table 4-7.
fileReference
On return, this value specifies a reference to the created image file.

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

DESCRIPTION
You need to override the GXCreateImageFile message if you are working with an output device that needs to be driven from a file. For example, a film recorder might need to process all of the data for a single image plane at once, due to hardware timing constraints. Or a facsimile machine might need to receive the data for a page without lengthy interruptions that indicate a disconnection. For devices with constraints like these, you need to send the printer data to a file that is subsequently streamed to the device.
When you create an imaging file, QuickDraw GX stores the printing data and plays it back to the output device in a steady stream. The options that you specify in the imageFileOptions parameter define how the playback occurs, as shown in Table 4-7.
The default implementation of this message creates the image file if the options specify that it should.
Table 4-7 Image file options
Constant Value Explanation
gxNoImageFile 0 The function does not create an image file. This is the default value.
gxMakeImageFile 1 The function creates an image file.
gxEachPlane 2 The function stores one image plane of data at a time. This allows a device like a film recorder to process each image plane of a data without pausing.
gxEachPage 4 The function stores one page of data at a time. This allows a device to process each page without pausing.
gxEntireFile 6 The function stores the entire document to allow the device to process the document without pausing.

SPECIAL CONSIDERATIONS
You never send the GXCreateImageFile message yourself.
You must forward the GXCreateImageFile message to other message handlers. You can modify the options and then forward the 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.

**Table 4-7 Image file options**
Constant	Value	Explanation
gxNoImageFile	0	The function does not create an image file. This is the default value.
gxMakeImageFile	1	The function creates an image file.
gxEachPlane	2	The function stores one image plane of data at a time. This allows a device like a film recorder to process each image plane of a data without pausing.
gxEachPage	4	The function stores one page of data at a time. This allows a device to process each page without pausing.
gxEntireFile	6	The function stores the entire document to allow the device to process the document without pausing.

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

GXCreateImageFile

DESCRIPTION

SPECIAL CONSIDERATIONS

RESULT CODES gxSegmentLoadFailedErrA required code segment could not be found, or there was not enough memory to load it. gxPrUserAbortErrThe user has canceled printing.

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.