function hout = subimage(varargin)
%SUBIMAGE Display multiple images in single figure.
%   You can use SUBIMAGE in conjunction with SUBPLOT to create
%   figures with multiple images, even if the images have
%   different colormaps. SUBIMAGE works by converting images to
%   truecolor for display purposes, thus avoiding colormap
%   conflicts.
%
%   SUBIMAGE(X,MAP) displays the indexed image X with colormap
%   MAP in the current axes.
%
%   SUBIMAGE(I) displays the intensity image I in the current
%   axes.
%
%   SUBIMAGE(BW) displays the binary image BW in the current
%   axes.
%
%   SUBIMAGE(RGB) displays the truecolor image RGB in the current
%   axes.
%
%   SUBIMAGE(x,y,...) displays an image with nondefault spatial
%   coordinates.
%
%   H = SUBIMAGE(...) returns a handle to the image object.
%
%   Class Support
%   -------------
%   The input image can be of class logical, uint8, uint16,
%   or double.
%
%   Example
%   -------
%       load trees
%       [X2,map2] = imread('forest.tif');
%       subplot(1,2,1), subimage(X,map)
%       subplot(1,2,2), subimage(X2,map2)
%
%   See also IMSHOW, SUBPLOT.

%   Copyright 1993-2004 The MathWorks, Inc.
%   $Revision: 1.1.8.1 $  $Date: 2004/08/10 01:50:39 $

[x,y,cdata] = parse_inputs(varargin{:});

ax = newplot;
fig = ancestor(ax,'figure');
cm = get(fig,'Colormap');

% Go change all the existing image and texture-mapped surface 
% objects to truecolor.
h = [findobj(fig,'Type','image') ; 
    findobj(fig,'Type','surface','FaceColor','texturemap')];
for k = 1:length(h)
    if (ndims(get(h(k), 'CData')) < 3)
        if (isequal(get(h(k), 'CDataMapping'), 'direct'))
            if (strcmp(get(h(k),'Type'),'image'))
                set(h(k), 'CData', im2uint8(ind2rgb(get(h(k),'CData'), cm)));
            else
                set(h(k), 'CData', ind2rgb(get(h(k),'CData'), cm));
            end
        else
            clim = get(ancestor(h(k),'axes'), 'CLim');
            data = get(h(k), 'CData');
            if (isa(data,'uint8'))
                data = double(data) / 255;
                clim = clim / 255;
            elseif (isa(data,'uint16'))
                data = double(data) / 65535;
                clim = clim / 65535;
            end
            data = (data - clim(1)) / (clim(2) - clim(1));
            if (strcmp(get(h(k),'Type'),'image'))
                data = im2uint8(data);
                set(h(k), 'CData', cat(3, data, data, data));
            else
                data = min(max(data,0),1);
                set(h(k), 'CData', cat(3, data, data, data));
            end
        end
    end
end

h = image(x, y, cdata);
axis image;

if nargout==1,
    hout = h;
end

%--------------------------------------------------------
% Subfunction PARSE_INPUTS
%--------------------------------------------------------
function [x,y,cdata] = parse_inputs(varargin)

x = [];
y = [];
cdata = [];
msg = '';   % empty string if no error encountered

scaled = 0;
binary = 0;

msg_aEqualsb = 'a cannot equal b in subimage(I,[a b])';
eid_aEqualsb = sprintf('Images:%s:aEqualsB',mfilename);

switch nargin
case 0
    msg = 'Not enough input arguments.';
    eid = sprintf('Images:%s:notEnoughInputs',mfilename);
    error(eid,'%s',msg);    
    
case 1
    % subimage(I)
    % subimage(RGB)
    
    if ((ndims(varargin{1}) == 3) && (size(varargin{1},3) == 3))
        % subimage(RGB)
        cdata = varargin{1};
        
    else
        % subimage(I)
        binary = islogical(varargin{1});
        cdata = cat(3, varargin{1}, varargin{1}, varargin{1});

    end
    
case 2
    % subimage(I,[a b])
    % subimage(I,N)
    % subimage(X,map)
    
    if (numel(varargin{2}) == 1)
        % subimage(I,N)
        binary = islogical(varargin{1});
        cdata = cat(3, varargin{1}, varargin{1}, varargin{1});
        
    elseif (isequal(size(varargin{2}), [1 2]))
        % subimage(I,[a b])
        clim = varargin{2};
        if (clim(1) == clim(2))
            error(eid_aEqualsb,'%s',msg_aEqualsb);
            
        else
            cdata = cat(3, varargin{1}, varargin{1}, varargin{1});
        end
        scaled = 1;
        
    elseif (size(varargin{2},2) == 3)
        % subimage(X,map);
        cdata = im2uint8(ind2rgb(varargin{1},varargin{2}));
        
    else
        msg = 'Invalid input arguments.';
        eid = sprintf('Images:%s:invalidInputs',mfilename);
        error(eid,'%s',msg);    
        
    end
        
case 3
    % subimage(R,G,B)  OBSOLETE
    % subimage(x,y,I)
    % subimage(x,y,RGB)
    
    if ((ndims(varargin{3}) == 3) && (size(varargin{3},3) == 3))
        % subimage(x,y,RGB)
        x = varargin{1};
        y = varargin{2};
        cdata = varargin{3};
        
    elseif (isequal(size(varargin{1}), size(varargin{2})) && ...
                isequal(size(varargin{2}), size(varargin{3})))
        % subimage(R,G,B)
        wid = sprintf('Images:%s:obsoleteSyntaxUse3D',mfilename);
        warning(wid,'%s %s','SUBIMAGE(R,G,B) is an obsolete syntax.',...
                'Use a three-dimensional array to represent RGB image.');
        cdata = cat(3, varargin{:});
        
    else
        % subimage(x,y,I)
        x = varargin{1};
        y = varargin{2};
        binary = islogical(varargin{3});
        cdata = cat(3, varargin{3}, varargin{3}, varargin{3});
        
    end
    
case 4
    % subimage(x,y,I,[a b])
    % subimage(x,y,I,N)
    % subimage(x,y,X,map)
    
    if (numel(varargin{4}) == 1)
        % subimage(x,y,I,N)
        x = varargin{1};
        y = varargin{2};
        binary = islogical(varargin{3});
        cdata = cat(3, varargin{3}, varargin{3}, varargin{3});
        
    elseif (isequal(size(varargin{4}), [1 2]))
        % subimage(x,y,I,[a b])
        scaled = 1;
        clim = varargin{4};
        if (clim(1) == clim(2))
            error(eid_aEqualsb,'%s',msg_aEqualsb);
        else            
            x = varargin{1};
            y = varargin{2};
            cdata = cat(3, varargin{3}, varargin{3}, varargin{3});
        end
        
    elseif (size(varargin{4},2) == 3)
        % subimage(x,y,X,map);
        x = varargin{1};
        y = varargin{2};
        cdata = im2uint8(ind2rgb(varargin{3},varargin{4}));
        
    else
        msg = 'Invalid input arguments';                
        eid = sprintf('Images:%s:invalidInputs',mfilename);
        error(eid,'%s',msg);            
        
    end
    
case 5
    % subimage(x,y,R,G,B) OBSOLETE
    
    if (~isequal(size(varargin{3}), size(varargin{4})) || ...
                ~isequal(size(varargin{4}), size(varargin{5})))
        msg = 'R, G, and B must be the same size in subimage(x,y,R,G,B)';
        eid = sprintf('Images:%s:RGBNotSameSize',mfilename);
        error(eid,'%s',msg);    
        
    else
        % subimage(x,y,R,G,B)
        wid = sprintf('Images:%s:obsoleteSyntaxUse3D',mfilename);
        warning(wid,'%s %s','SUBIMAGE(x,y,R,G,B) is an obsolete syntax.',...
                'Use a three-dimensional array to represent RGB image.');
        x = varargin{1};
        y = varargin{2};
        cdata = cat(3, varargin{3:5});
    end
    
otherwise
    msg = 'Too many input arguments';
    eid = sprintf('Images:%s:tooManyInputs',mfilename);
    error(eid,'%s',msg);        
    
end

if (isempty(msg))
    if (scaled)
        if (isa(cdata,'double'))
            cdata = (cdata - clim(1)) / (clim(2) - clim(1));
            cdata = min(max(cdata,0),1);
            
        elseif (isa(cdata,'uint8'))
            cdata = im2double(cdata);
            clim = clim / 255;
            cdata = (cdata - clim(1)) / (clim(2) - clim(1));
            cdata = im2uint8(cdata);
            
        elseif (isa(cdata,'uint16'))
            cdata = im2double(cdata);
            clim = clim / 65535;
            cdata = (cdata - clim(1)) / (clim(2) - clim(1));
            cdata = im2uint8(cdata);
            
        else
            msg = 'Class of input image must be uint8, uint16, or double.';
            eid = sprintf('Images:%s:invalidClass',mfilename);
            error(eid,'%s',msg);    
            
        end
        
    elseif (binary)
        cdata = uint8(cdata);
        cdata(cdata ~= 0) = 255;
    end
    
    if (isempty(x))
        x = [1 size(cdata,2)];
        y = [1 size(cdata,1)];
    end
end

% Regardless of the input type, at this point in the code,
% cdata represents an RGB image; atomatically clip double RGB images 
% to [0 1] range
if isa(cdata, 'double')

   cdata(cdata > 1) = 1;
   cdata(cdata < 0) = 0;
end