% for NEGATIVE PRINT OF IMAGE; often saves toner.       Steve Mann; 1990OCT22
%
% places GRID (crosshairs at origin only) into image
%
% scales a real matrix to [0,255] range, takes 255-image,
% and places a border of all black (zeros) around the outside.
% the dimension is increased by 2 (or more) each way
%
% Y = border(X);       % black border all around
%                      % so if image is mostly white, you can see its region of support
%
% Y = border(X,2);     % double thickness border all around
%
% Y = border(X,3,4);   % 3 rows of zeros, 4 cols of zeros;
%                      % looks nice on a 3by4 image (eg. TV screen size)

function Y = dummy(X,thicknessrow,thicknesscol)

if nargin == 2
  thicknesscol = thicknessrow;
end%if
if nargin == 1
  thicknesscol = 1;
  thicknessrow = 1;
end%if

[M N] = size(X);

%%%X = scaler2_steve(X);
X = scaler2(X);
% CROSSHAIRS at origin
X(M/2,:) = 255*ones(1,N);  % white now, will be black when neg. taken
X(:,N/2) = 255*ones(M,1);

rowpad = zeros(thicknessrow,N);
colpad = zeros(M+2*thicknessrow,thicknesscol);

Y = [colpad [rowpad;255-X;rowpad] colpad];

dis = sprintf('  to  %g by %g, took NEGATIVE and SCALED to [0,255]',M+2*thicknessrow,N+2*thicknesscol);
disp([sprintf('zero padded  %g by %g',M,N) dis])
