NAME:			Pointsample

AUTHOR INFO:	Ian J. Curington
                Stardent Computer Limited
                15 Frederick Sanger Road
                The Surrey Research Park
                Guildford
                Surrey    GU2 5YD
                United Kingdom
                +44-483-505388
                email: ianc@Stardent.COM

SOURCE FILE:	pointsample.f

TYPE:			renderer

INPUTS:			field 2d uniform scalar float

OUTPUTS:		formatted numerical text to standard-output

PARAMETERS:
        Name        Type    Default     Min    Max
        ----        ----    -------     ---    ---		
        X Position  integer       1       1    999
        Y Position  integer       1       1    999

DESCRIPTION:
	Pointsample extracts a single scalar value out of the input
2D scalar floating point field. The X and Y position parameters set
the index point for the sample to be taken from the field.
The numerical field value is then sent to stdout, usually into the
window where avs was invoked. The one line message consist of
the current X and Y sample index position, and the floating point
value of the field at that point. The position values are clamped
to the field dimensions internally, without regard to the dial min-max.
This module does virtually no work, so "immediate" mode is recommended
on the dials. The author has used this for debugging other networks
and filters, by linking it in with a "t" junction to other more
complex networks.

EXAMPLE: This network is a demonstration  usage of the pointsample module.
The EXTRACT SCALAR is used to derive a scalar field from a vector field (image)


    +------------------------+
    |     READ IMAGE         |
    +------------------------+
            |
            |--------------------------------------+
            |                                      |
    +------------------------+              +----------------------+
    |    EXTRACT SCALAR      |  (set to 1)  | Display Image        |
    +------------------------+              +----------------------+
            |
    +------------------------+
    |    FIELD to FLOAT      |
    +------------------------+
            |
    +------------------------+
    |    POINTSAMPLE         |
    +------------------------+