QUERY_PPM

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.

Syntax

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.


5.2	Introduced