Matlab function that accepts figure handle or file name as input?

I want to write a matlab function that except one input argument, it can be a figure handle or file name to .fig file. If no input is provided I will invoke uigetfile. So far I can not get my function accept figure handle and modify the plot. Remember code should also check if the input is figure-handle or file name. Please help me with this.

function []=changexlim(varargin)
% This function changes xlim for various values and 
narginchk(0,1)
if nargin==0
    [file,path]=(uigetfile('*.fig','Select matlab figure'));
    fil=fullfile(path,file);
    openfig(fil)
    xlim([0 5])
end

if nargin==1
    check=ishandle(varargin)
    if check==1
        gca=get(varargin,'CurrentAxis')
        xlim(gca,[0 5])
    else if check==0
         openfig(varargin)
         xlim([0 5])    
        end
    end

figure(varargin)
end

Answer 1

[Walter Roberson]

If you are using R2014b or later, it is recommended that you use isgraphics instead of ishandle()

Once you think you have a graphics handle, you should examine its type property to determine whether it is a figure. Or you could use ancestor(TheHandle,'figure') to find the figure in case you were handed some other graphics object.

In your code you are operating on varargin . You should instead be operating on varargin{1} for the first parameter.

The correct property name is CurrentAxes not CurrentAxis . And you need to be careful because it can be empty for various reasons.

You should never assign to a variable named "gca" as doing so interferes with using the gca function.

In the case where you are handed a string, check is false, and you openfig() . That is fine so far once you correct varargin to varargin{1} . But after the "end" of the "else", you assume you can figure(varargin) and even if you figure(varargin{1}) you have made the assumption that you can figure() a string .

What you should be doing is assigning the output of openfig() to a variable, and then figure() the variable.

[Samir]

Thank you it works!

[Samir]

Thnak you for the answer, I have one more question.

In the code given below in case of either uigetfile or filename.fig inputs my function will open the figure and change the limit, however if the figure handle is given it will change the xlim of existing figure. I want it to open the figure in separate window using the supplied handle and then do the changes

function []=changexlim(varargin)
% This function changes xlim for various values and 
% generates animated gif
narginchk(0,1)
if nargin==0
    [file,path]=(uigetfile('*.fig','Select matlab figure'));
    fil=fullfile(path,file);
    sprintf('User selected %s',fil)
    fh=openfig(fil);
    disp('figure handle returned to fh using uigetfile')
end

if nargin==1
    check=ishandle(varargin{1});
    if check==1
        fh=varargin{1};
       disp('User supplied figure handle returned to fh') 
    else if check==0
         fh=openfig(varargin{1},'invisible');
         disp('User supplied .fig files handle was returned to fh')    
        end
    end

ax=get(fh,'CurrentAxes');
xl=xlim(ax);
N=10;
dx=getdx(xl,N);
m=N;
for ii=1:10
    if ( xl(1)+(dx*ii))>=(xl(2)-(dx*ii)); % Check if lowerlimit>upperlimit
         m=2*m;
         xl=cat(2,d1,d2);
         dx=getdx(xl,m); % IF ture reduce the dx before going forward
    end

      y=input('Press enter');
      d1=xl(1)+(dx*ii);
      d2=xl(2)-(dx*ii);

      xlim(ax,[d1 d2])

end

end %End naragin
end % End Function

function dx=getdx(xl,N)
dx=(xl(2)-xl(1))/N;

end

[Walter Roberson]

Naming a variable "path" can cause nasty problems as "path" is used by MATLAB to figure out where to find routines.

You cannot open a figure in a new window: a figure is a window. But you can make a copy of it:

groot = 0;         %See note!
fh = copyobj(varargin{1}, groot);

Note: remove the assignment statement

groot = 0;

if you are using R2014b or later! R2014b and later already assigns it and may get confused if you re-assign it.

[Samir]

Thank you for the prompt answer. I will take care of path variable. Also I found a work around by temporary saving the figure as .fig. See code below.

if nargin==1
  check=ishandle(varargin{1});
  if check==1
      fh=varargin{1};
     disp('User supplied figure handle returned to fh') 
     fsave=tempname;
     saveas(fh,fsave);
     disp('Temporary figure saved')
     fh=openfig(fsave);