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function [X, map] = readras(filename, ys, ye, xs, xe);
%READRAS Read an image file in sun raster format.
% READRAS('imagefile.ras') reads a "sun.raster" image file.
% [X, map] = READRAS('imagefile.ras') returns both the image and a
% color map, so that
% [X, map] = readras('imagefile.ras');
% image(X)
% colormap(map)
% axis('equal')
% will display the result with the proper colors.
% NOTE: readras cannot deal with complicated color maps.
% In fact, Matlab doesn't quite allow to work with colormaps
% with more than 64 entries.
%
%%
%% (C) Thomas K. Leung 3/30/93.
%% California Institute of Technology.
%% Modified by Andrea Mennucci to deal with color images
%%
% PC and UNIX version of readras - Jean-Yves Bouguet - Dec. 1998
dot = max(find(filename == '.'));
suffix = filename(dot+1:dot+3);
if(strcmp(suffix, 'ras')) % raster file format %
fp = fopen(filename, 'rb');
if(fp<0) error(['Cannot open ' filename '.']), end
%Read and crack the 32-byte header
fseek(fp, 4, -1);
width = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
height = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
depth = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
length = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
type = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
maptype = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
maplen = 2^24 * fread(fp, 1, 'uchar') + 2^16 * fread(fp, 1, 'uchar') + 2^8 * fread(fp, 1, 'uchar') + fread(fp, 1, 'uchar');
maplen = maplen / 3;
if maptype == 2 % RMT_RAW
map = fread(fp, [maplen, 3], 'uchar')/255;
% if maplen<64, map=[map',zeros(3,64-maplen)]';maplen=64; end;
elseif maptype == 1 % RMT_EQUAL_RGB
map(:,1) = fread(fp, [maplen], 'uchar');
map(:,2) = fread(fp, [maplen], 'uchar');
map(:,3) = fread(fp, [maplen], 'uchar');
%maxmap = max(max(map));
map = map/255;
if maplen<64, map=[map',zeros(3,64-maplen)]'; maplen=64; end;
else % RMT_NONE
map = [];
end
% if maplen>64,
% map=[map',zeros(3,256-maplen)]';
% end;
% Read the image
if rem(width,2) == 1
Xt = fread(fp, [width+1, height], 'uchar');
X = Xt(1:width, :)';
else
Xt = fread(fp, [width, height], 'uchar');
X = Xt';
end
X = X + 1;
fclose(fp);
else
error('Image file name must end in either ''ras'' or ''rast''.');
end
if nargin == 5
X = X(ys:ye, xs:xe);
end
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