Hi,

I have trouble understanding a fundamental concept in Java 2D.
To give a specific example:
One can customize a swing component via implementing it's own version of the method paintComponent(Graphics g)
Graphics is available to the body of the method.
Question:
What is exactly this Graphics object, I mean how it is related to the object that has the method paintComponent? Ok, I understand that you can do something like:

g.setColor(Color.GRAY);
g.fillOval(0, 0, getWidth(), getHeight());

To get a gray oval painted. What I can not understand is how is the Graphics object related to the component and the canvas. How is this drawing actually done?
Another example:

public class MyComponent extends JComponent {

     protected void paintComponent(Graphics g) {

                System.out.println("Width:"+getWidth()+", Height:"+getHeight());

            }

    public static void main(String args[]) {

                JFrame f = new JFrame("Some frame");
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.setSize(200, 90);
                MyComponent  component = new MyComponent  ();
                f.add(component);
                f.setVisible(true);       
          }
 }

This prints

Width:184, Height:52

What does this size mean? I have not added anything to the frame of size(200,90).
Any help on this is highly welcome

Thanks