TYPE: COP
TITLE: Composite COP

This operation does a composite (over, under, inside, add, etc) between two
images. The first image is the foreground, which may be translated relative
to the second input, the background. The size of the resulting image is the
size of the background image.

The Layer COP allows multiple inputs to be composited together instead of
just two.

Parameters
Composite
    Operation       - Specifies the compositing operation:
	Over     - Places the foreground over the background.
	Under    - Places the foreground under the background's alpha.
	Atop     - Places the foreground over the background only where
		   the background alpha exists.
	Inside   - Places the foreground inside the background's alpha.
	Outside  - Places the foreground outside the background's alpha.
	Screen   - Inverts both, multiplies, inverts the product.
	Add      - Adds the foreground to the background.
	Subtract - Subtracts the foreground from the background.
	Diff     - Takes the absolute difference between the foreground
		   and the background.
	Multiply - Multiplies the background by the foreground.
	Minimum  - Takes the minimum of the foreground and background.
	Maximum  - Takes the maximum of the foreground and background.
	Average  - Takes the average of the foreground and background.

    Image Units        - Selects pixels or UV units for the transform.
    Translate, Rotate, Scale, Pivot - Transforms the foreground in X,Y
			 relative to the background.
    Image Filter       - Specifies the filter to use when transforming.
    Image Wrap         - Sepcifies the foreground image's wrapping style. 
    Motion Blur        - Toggles on motion blur, and specifies the time range
                          around the current frame to blur.
    Motion Frame Bias  - Shifts the time range for the blur.
    Motion Blur Segments - Number of samples to blur together in the specified
                           time range.
    Motion Blur Method - 
        Velocity    - Only uses the current frame and the transform to compute
                      past and future positions.
        Deformation - Cooks the images at all time samples.

Merge
    Overview     - These parameters specify how to build the output
		   sequence when there are differences between the
		   input sequences.
    Plane Merge  - If the planes in the inputs differ, this specifies
		   what the output planes should be. 
    Raster Depth - If the raster depth for a given plane differs between
		   inputs, this specifies when the output raster depth for
		   the plane should be.
    Frame Range  - If the frame ranges of the inputs differ, this
		   determines what the output range should be.
    Frame Rate   - If the frame rates of the inputs differ, this
		   determines what the output frame rate should be.
    Frame Match  - If the frame rates of the inputs differ, this
		   determines which input frame to pick when the cook time
		   doesn't reside on a frame boundary.

Local Variables:
    L   - Sequence length
    S   - Start of sequence
    E   - End of sequence
    IL  - Input sequence length
    SR  - Sequence frame rate
    NP  - Number of planes in sequence
    W,H - Width and height of image
    I   - Image index (0 at start frame)
    IT  - Image time (0 at start frame)
    AI  - Current plane array index
    PI  - Current plane index
    PC  - Num of channels in current plane

See Also: Layer
