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    <p>You may need to fill your matrix with default valued lines in order to create it. The typical approach to preallocating a matrix of objects of size <code>N</code> would be to simply assign an object to the last element in the matrix.</p> <pre><code>M(N,N)=imline(gca,[NaN NaN],[NaN NaN]); %# set non-displayable vals for x and y </code></pre> <p><strong>NOTE, the line above will not work with <code>imline</code></strong> as it will call the default constructor for each of the other N*N-1 imline objects in the matrix and a call of <code>imline</code> with no arguments forces user interaction with the current axis. </p> <p>My advice (if you are pre-allocating) is to define all the default lines <em>explicitly</em> in the matrix:</p> <pre><code>for k=1:N*N M(k)=imline(gca,[NaN NaN],[NaN NaN]); end %# Reshape (if necessary) M = reshape(M,[N N]); </code></pre> <p>Alternatively, you could let Matlab fill the array for you. If you find that you will need this code often, derive a new class from <code>imline</code>. The following example shows the very least that would need to happen. It merely defines a constructor. This example allows you to pass optional arguments to <code>imline</code> as well. If no arguments are specified, the <code>imline</code> object is created with position values as above. </p> <pre><code>classdef myimline&lt;imline methods function obj = myimline(varargin) if isempty(varargin) varargin = {gca,[NaN NaN],[NaN NaN]}; end obj = obj@imline(varargin{:}); end end end </code></pre> <p>Example usage:</p> <pre><code>%# Generate a 100 element array of `imline` objects, %# but define the last one explicitly mat(100)=myimline(gca,[0 1],[0 1]); </code></pre> <p>The last <code>myimline</code> object in the array has points specified as in the assignment, but the rest of the elements have the default position values <code>[NaN NaN]</code> as above. </p>
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    1. POStoring handles of objects generated by imline in MATLAB
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    1. POStoring handles of objects generated by imline in MATLAB
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    1. COThanks, this worked. On a related note, does MATLAB have a tool which would optimize creating a matrix of this kind (other than by loop, as we've done here)?
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    2. CO@Adam, the problem here is merely that the default constructor for `imline` objects is an interactive function. In most other cases, we could just construct the entire array by assigning an object to the last element. Here is a [reference](http://www.mathworks.de/help/techdoc/matlab_oop/brd4btr.html). Note that the typical approach to generating arrays of objects is to use a loop. If it were me, and I was going to use this alot, I would consider deriving a new class which inherits from `imline` in which I define my own constructor. Hope this helps.
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    3. COThanks, I'll be looking into classdef for future use.
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