title: howto set the size of a Canvas, which doesn't have a layout
body: <p>I am subclassing the Canvas in SWT, and calling pack() inside of the constructor,
  the Canvas' size is computed as 64x64.</p>
  
  <p>There is no Style or layout inside of my class.</p>
  
  <ul>
  <li>How is the size computed at this here?</li>
  <li>How can I change the size of my class?  <code>this.setSize()</code> doesn't work.</li>
  </ul>
  
  <pre>
  <code>
      public MyClass(Composite parent, int style) {
          super(parent, SWT.NONE);
          this.setBackground(getDisplay().getSystemColor(SWT.COLOR_YELLOW));
  
          this.computeSize(1000, 1000, true);
          this.pack();
  
          Point s = this.getSize();
          System.out.println(s.x); //prints 64
      }
  </code>
  </pre>