 the AlphaData accordingly</p><p><b>Paramters</b></p><p><tt>x</tt>: x coordinate</p><p><tt>y</tt>: y coordinate</p><pre class="codeinput">        <span class="keyword">function</span> paint(obj, x, y)
            img = obj.getCData();
            img(y, x) = 1;
            obj.setCData(img);
            obj.setAlphaData(img);
        <span class="keyword">end</span>
</pre><h2>unpaint<a name="14"></a></h2><p>Remove a point to the CData and update the AlphaData accordingly</p><p><b>Paramters</b></p><p><tt>x</