PNM

		type String2
	A string of 2 characters. Used for magic numbers in PNM files.

Headers with Maxval

		procedure Read_Header
	Read a PNM file header, with Maxval (for PGM and PPM).
	Param  Type  Description in Stream  Stream_Access  Read from this stream. out Magic  String2  Magic number for PNM file type. out Width  Positive  Width of the image in pixels. out Height  Positive  Height of the image in pixels. out Maxval  Positive  Maximum pixel component value.

		procedure Write_Header
	Write a PNM file header, with Maxval (for PGM and PPM).
	Param  Type  Description in Stream  Stream_Access  Write to this stream. in Magic  String2  Magic number for PNM file type. in Width  Positive  Width of the image in pixels. in Height  Positive  Height of the image in pixels. in Maxval  Positive  Maximum pixel component value.

Headers without Maxval

		procedure Read_Header
	Read a PNM file header, without Maxval (for PBM).
	Param  Type  Description in Stream  Stream_Access  Read from this stream. out Magic  String2  Magic number for PNM file type. out Width  Positive  Width of the image in pixels. out Height  Positive  Height of the image in pixels.

		procedure Write_Header
	Write a PNM file header, without Maxval (for PBM).
	Param  Type  Description in Stream  Stream_Access  Write to this stream. in Magic  String2  Magic number for PNM file type. in Width  Positive  Width of the image in pixels. in Height  Positive  Height of the image in pixels.