PreviewMakePreview(IM: QC)

Inside Macintosh: QuickTime Components /

Chapter 12 - Preview Components / Preview Components Reference

PreviewMakePreview
The PreviewMakePreview function creates previews by allocating a handle to data that is to be added to the file.
pascal ComponentResult PreviewMakePreview (pnotComponent p,
                                 OSType *previewType,
                                 Handle *previewResult,
                                 const FSSpec *sourceFile,
                                 ProgressProcRecordPtr progress);
p
Specifies your preview component. You obtain this identifier from
the Component Manager's OpenComponent function. See the chapter "Component Manager" in Inside Macintosh: More Macintosh Toolbox for details.
previewType

Contains a pointer to the type of preview component that should be used to display the preview.
previewResult
Contains a pointer to a handle of cached preview data created by this function.
sourceFile
Contains a pointer to a reference to the file for which the preview is created.
progress
Points to a progress function. For details on progress functions, see the chapter "Image Compression Manager" in Inside Macintosh: QuickTime. If the process of creating a preview takes more than a few seconds, you should call the progress function that is provided.

DESCRIPTION
Your preview component should not actually write the preview to the given file. It should simply return the handle. The data is added to the file by the caller.