TYPE: COP
TITLE: Unpin COP

This operation allows you to extract an arbitrary quadrilateral area out of 
the input image and stretch it to fill the full resolution of the output. It is
the opposite of corner pin.

Four points are used to define the desired area of the input image. Image data 
outside the desired area is discarded.

In the viewport, Right Click or press 'e' (default hotkey) to edit the handles
on the input image. Right click again or press 'e' to return to viewing the 
output of this node.

Parameters
UnPin
    Units             - Specifies the units of the point coordinates.
    Bottom Left, Bottom Right, Top Left, Top Right - The four corner points
                                                     of the input area.
    Filter            - The filter to use when scaling the image to fit
                        the new area.

Plane Scope, Frame Scope
    Overview - See extra help (Middle click on the dialog '?' help).

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
