.LP
These routines perform logic operations on a pixel by pixel basis.
.SH
SHORT DESCRIPTION OF ROUTINES
.IP "And - " 
Logically AND two images pixel by pixel.
.IP "Or -" 20
Logically OR two images pixel by pixel.
.IP "Xor -" 20
Exclusive OR two images pixel by pixel.
.IP "Right Shift -" 20
Right shift each pixel value in an image (using an operation gating mask).
.IP "Left Shift -" 20
Left shift each pixel value in an image (using an operation gating mask).
.IP "Replace -" 20
Replace pixels of the first input image with pixels of the second
according to a mask.
