Skip to main content

Responsive MATLAB GUI without calling drawnow() directly


Facts about MATLAB:



  1. MATLAB UI is Java Swing.

  2. MATLAB has excellent interoperability with Java, it is possible to initialize Java objects and call their methods directly from MATLAB code, it is even possible to pass in MATLAB defined listeners to Java!



My problem:



MATLAB does not offer background threads, so to make MATLAB UI responsive we have to call function drawnow which flushes Swing EDT queue, see also here and here . This is a known fact, so far so good.



But now I have a customer whose code which performs the computation is a MATLAB p-file (encrypted) so I have no access to the code to put drawnow there.



Unsuccessful attempt:



I tried spinning up a timer to do the job of calling drawnow but it does not seem to work - timer itself needs a precedent drawnow to fire its callbacks.



EDIT: At the end I implemented GUI with .NET/WPF running on another thread, so it remains always responsive and looks much better then original MATLAB.


Source: Tips4allCCNA FINAL EXAM

Comments

  1. I don't know whether this can be done properly. I've never found a way of getting the effect of drawnow in the middle of a mex file, and I would guess this situation is similar. But here is an incredibly messy hack anyway :D. If you have a p-file, you can run:

    profile on;
    pfile();
    profile viewer;


    and get an idea of what functions pfile() is calling. If the code is calling any built-in functions (e.g. disp) or any function whose source-code you have access to, you can create your own version of that file further up the path, which will be called by the p-file, e.g.

    function disp(X)
    if (toc > 5)
    drawnow;
    tic;
    end
    builtin('disp', X);


    This will call drawnow at most once every 5 seconds, though it won't be much use unless disp were called regularly. If you can't find a builtin to override, you could use any other function and just insert the drawnow part at the top, like:

    function primes(N)
    if (toc > 5)
    drawnow;
    tic;
    end
    The rest of the original primes.m here.

    ReplyDelete
  2. Just an idea. You could build a jar file from the p-file using Matlab builder for java.
    From within Java you could do the calculation now in a separate thread.

    ReplyDelete

Post a Comment

Popular posts from this blog

[韓日関係] 首相含む大幅な内閣改造の可能性…早ければ来月10日ごろ=韓国

div not scrolling properly with slimScroll plugin

I am using the slimScroll plugin for jQuery by Piotr Rochala Which is a great plugin for nice scrollbars on most browsers but I am stuck because I am using it for a chat box and whenever the user appends new text to the boxit does scroll using the .scrollTop() method however the plugin's scrollbar doesnt scroll with it and when the user wants to look though the chat history it will start scrolling from near the top. I have made a quick demo of my situation http://jsfiddle.net/DY9CT/2/ Does anyone know how to solve this problem?

Why does this javascript based printing cause Safari to refresh the page?

The page I am working on has a javascript function executed to print parts of the page. For some reason, printing in Safari, causes the window to somehow update. I say somehow, because it does not really refresh as in reload the page, but rather it starts the "rendering" of the page from start, i.e. scroll to top, flash animations start from 0, and so forth. The effect is reproduced by this fiddle: http://jsfiddle.net/fYmnB/ Clicking the print button and finishing or cancelling a print in Safari causes the screen to "go white" for a sec, which in my real website manifests itself as something "like" a reload. While running print button with, let's say, Firefox, just opens and closes the print dialogue without affecting the fiddle page in any way. Is there something with my way of calling the browsers print method that causes this, or how can it be explained - and preferably, avoided? P.S.: On my real site the same occurs with Chrome. In the ex