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POImage Processing, extending JPanel and Simulating Classes in Clojure
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  1. POImage Processing, extending JPanel and Simulating Classes in Clojure
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    copied!<p>there! I'm building an image-processing application in swing/clojure, and right now I need to develop an image panel in which I can click and compute data. Thanks to <a href="https://stackoverflow.com/questions/1516287/using-swing-i-want-to-draw-a-couple-of-points">coobird</a>, I now have a good idea on how to do it in Java, but I still don't get many issues on its integration with Clojure.</p> <p>Let's take a look at how coobird suggested me doing. First, we should extend a class in Java. In clojure, we do this with the <code>proxy</code> macro, so we'd have something like this:</p> <pre> (def painting-panel (proxy [JPanel] [])) </pre> <p>The next step is to create the class constructor and set some variables. </p> <ol> <li><p>I can define functions after the second argument of proxy, but how can I create the constructor? Is painting-panel the name of this class (therefore the name of the function I should create)?</p></li> <li><p>How can I deal with class variables? Should I define them with a <code>let</code>, like I did?</p></li> <li><p>Are <code>this</code> and <code>super</code> available for me to use, like I did below?</p></li> </ol> <pre> (def painting-panel (let [background-image (Image.) point-clicked (Point.)] (proxy [JPanel] [] (paintComponent [g] (do ((.paintComponent super) g) (doto g (.drawImage background-image 0 0 nil) (.fillRect (.x point-clicked) (.y point-clicked) 1 1)))) (painting-panel []; constructor? ((.addMouseListener this) (proxy [MouseAdapter] [] (mouseClicked [e] (do (def point-clicked (.getPoint e)) (.repaint this))))))))) </pre> <p>Suggestions and code corrections are also welcome!</p> <p>Thank you!</p>
 

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