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function bmpwrite(X,map, filename);  
%BMPWRITE Write a BMP (Microsoft Windows Bitmap) file to disk.  
%	BMPWRITE(X,MAP,'filename') writes a BMP file containing the  
%	indexed image X and colormap MAP to a disk file called 'filename'.  
%	If no file extension is given with the filename, the extension  
%	'.bmp' is assumed.  
%  
%	See also: BMPREAD, GIFWRITE, HDFWRITE, PCXWRITE, TIFFWRITE,  
%	          XWDWRITE.  
  
%	Mounil Patel 3/10/94  
%	Copyright (c) 1994 by The MathWorks, Inc.  
%	$Revision: 1.13 $  $Date: 1995/02/09 15:28:11 $  
  
if (nargin~=3)  
	error('Requires three arguments.');  
end;  
  
if (isstr(filename)~=1)  
	error('Requires a string filename as the third argument.');  
end;  
  
if (isempty(findstr(filename,'.'))==1)  
	filename=[filename,'.bmp'];  
end;  
  
fid=fopen(filename,'wb','l');  
if (fid==-1)  
	error(['Error opening ',filename,' for output.']);  
end;  
  
fwrite(fid,[66;77],'uchar');  
  
[biHeight,biWidth]=size(X);  
% What will be the physical file size?  First term: image data,  
% with width padded to be multiple of 4.  Second term: length of  
% bitmap header.  Third term: length of bitmap information  
% header.  Third term: length of color palette.  
bfSize = biHeight*(biWidth+(4-rem(biWidth,4))) + 14 + 40 + 256*4;  
fwrite(fid,bfSize,'uint');  
bfReserved1=0;  
fwrite(fid,bfReserved1,'ushort');  
bfReserved2=0;  
fwrite(fid,bfReserved2,'ushort');  
bfOffBytes=1078;  
fwrite(fid,bfOffBytes,'uint');  
biSize=40;  
fwrite(fid,biSize,'uint');  
  
fwrite(fid,biWidth,'uint');  
fwrite(fid,biHeight,'uint');  
biPlanes=1;  
fwrite(fid,biPlanes,'ushort');  
biBitCount=8;  
fwrite(fid,biBitCount,'ushort');  
biCompression=0;  
fwrite(fid,biCompression,'uint');  
biSizeImage=biHeight*(biWidth+(4-rem(biWidth,4)));  
fwrite(fid,biSizeImage,'uint');  
biXPels=0;  
fwrite(fid,biXPels,'uint');  
biYPels=0;  
fwrite(fid,biYPels,'uint');  
biClrUsed=256;  
fwrite(fid,biClrUsed,'uint');  
biClrImportant=0;  
fwrite(fid,biClrImportant,'uint');  
  
[m,n]=size(map);  
if (m<256)  
	map=[map;zeros(256-m,3)];  
elseif (m>256)  
 error('Colormap exceeds 256 colors! Only 8-bit BMP file output is supported.');  
end;  
  
map=[fliplr(map*255),zeros(256,1)]';  
fwrite(fid,map(:),'uchar');  
  
X=(X-1);  
if (rem(biWidth,4)~=0)  
	X=[X,zeros(biHeight,4-rem(biWidth,4))];  
end;  
X=rot90(X,3);  
fwrite(fid,X(:),'uchar');  
  
fclose(fid);