function [x,y] = zigzag(p,q);%function to generate a zig-zag scan pattern%(p,q) is current pixel position;(x,y) is next pixel position in the zigzag path if (p == q),   if ( mod(p,2) == 0 ),      x = p; y = q - 1;   else      x = p - 1; y = q;   end   elseif (p > q),   if( mod(p,2) == 0 ),      x = p;y = q - 1;   else      x = p;y = q + 1;   end   else   if( mod(q,2) == 0 ),      x = p + 1; y = q;   else      x = p - 1; y = q ;   endendif (x == 0 ),   x = 1; y = y + 1;endif (y == 0 ),   x = x + 1; y = 1;end