
@C1@c@b@_ Convolution 

     Read in an externally defined (square) matrix and convolve with
     the current image. The transformed image replaces the current image
     if successful.

@b Format
     The convolution matrix definitions must start with the at sign (@).
     Any line that does not start with at sign is considered to be
     comments and is silently ignored.

     The convolution matrix must have the following format:
@f   @label; n; n1, n2, n3 ,....;
     where label is the kernel name and is used to label the activation
     button; n is the order of the square matrix and n1, n2, n3 etc. are
     the matrix elements in column major, i.e., n1 is the (0,0) element,
     n2 is the (0,1) element etc. The matrix need not to be normalized.
     The following is a valid definition to sharpen an image:
@f   @sharpen; 3; 0, -1, 0, -1, 10, -1, 0, -1,0;

     See Also /usr/local/lib/bit/BIT_convolve for examples.

@b Locations
    Convolution matrix definition file must be named BIT_convolve.
    Bit searches for it in system directory /usr/local/lib/bit,
    current directory, and $HOME/.bitrc. All valid definitions found
    are concatenated with repeats removed.

