TYPE: CHOP
TITLE: Image CHOP

This CHOP converts rows and/or columns of pixels in an image to CHOP channels.
It generates one CHOP channel per span of pixels in the image. Pixels, rows,
columns or rectangular regions can be extracted from the image.

There is an optional input which supplies UV coordinates to sample the image.
The input CHOP must contain 2 channels, for U and V. The first channel is
always assumed to be U. The channels produced (red, green, blue and alpha) will
be exactly as long as the input channel's length, with a value for each UV
coordinate.

There are no local variables.

Parameters
Image
    Source        - Specify the COP Network, and the COP here as the
		    source from which the image should be obtained.
    Frame         - The frame number from which to obtain the image.  /frame
    Red, Green, Blue, Alpha - Creates a CHOP channel per scanline with the
                    prefix specified here, starting at 0. For example,
                    the default is "r" in the Red field. If the
                    specified COP is a horizontal ramp that is 5 lines
		    high, it creates five CHOP channels (r0 - r4)
		    using the values of the red pixels in those
		    scanlines.
    RGBA Units    - Scales the output to lie in the range 0-1, 0-255
		    or 0-65535.

Crop
    Crop          - Specifies what to extract from the image.
    UV Units      - Specifies the units for the following 4 parameters.
    U Start       - Starting point for sampling in U. Values          /ustart
		    outside the range of the image are determined by
		    the image's extend conditions, in the extend page.
    U End         - Ending point for sampling in U.                   /uend
    V Start       - Starting point for sampling in V.                 /vstart
    V End         - Ending point for sampling in V.                   /vend
    Interpolate   - Determines the interpolation method when
		    UV sampling with an input CHOP is used.
Extend
    Image Left    - The image extend conditions when sampling the
		    image with U less than 0.
    Image Right   - The image extend conditions for U greater than 1.
    Image Bottom  - The image extend conditions for V less than 0.
    Image Top     - The image extend conditions for V greater than 1.
	            The extend conditions are:
	Hold          - Use the first or last pixel value.
	Cycle         - Loop back to the other side of the image.
	Mirror        - Zig-zap back into the image.
	Default Color - Use a default color specified below.
    Default Color - The color to use when outside the bounds of the image,
		    and the Default Color extend condition is set.

See also: Geometry, Particle, Shuffle
