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IDL Reference Guide: Procedures and Functions |
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QUERY_PPM is a method of obtaining information about a PPM image file without having to read the file. See QUERY_* Routines for more information.
Result = QUERY_PPM ( Filename [, Info] [, MAXVAL=variable] )
This routine returns a long with the value of 1 (one) if the query was successful (and the file type was correct) or 0 (zero) on failure.
A scalar string containing the pathname of the PPM file to query.
Returns an anonymous structure containing information about the image. The Info.TYPE field will return the value `PPM'.
Additional field in the Info structure: MAXVAL - maximum pixel value in the image.
| Note See General Query * Routine Info Structures for detailed structure information. |
Set this keyword to a named variable to retrieve the maximum pixel value in the image.
QUERY_* Routines, READ_PPM, WRITE_PPM
IDL Online Help (March 06, 2007)