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javaswinggraphics2dpaintcomponent

Java - Swing - Graphics 2D

public class Points extends JPanel {

  public void paintComponent(Graphics g) {
  super.paintComponent(g);

  Graphics2D g2d = (Graphics2D) g;

  g2d.drawLine(60, 20, 80, 90);
 }
}

I'm not really sure what's the Graphics2D g2d = (Graphics2D) g; supposed to do.

It's just a plain JPanel that's later added onto a JFrame.

It would be really helpfull if anyone could give me some advice as I'm stuck at this line of the code for a long time now.

Solution

  • The statement

    Graphics2D g2d = (Graphics2D) g;

    just casts the Graphics object to a Graphics2D. It's used to access the methods provided by Graphics2D. In this case it is unnecessary as Graphics also has a drawLine method so if you don't have a requirement for the more advanced methods such as rotate and translate, you can use

    @Override
public void paintComponent(Graphics g) {
   super.paintComponent(g);
   g.drawLine(60, 20, 80, 90);
}