Java GradientPaint .createContext (ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform xform, RenderingHints hints)

public PaintContext createContext(ColorModel cm,    Rectangle deviceBounds,    Rectangle2D userBounds,    AffineTransform xform,    RenderingHints hints)

import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;
import java.awt.image.ColorModel;
//from ww w .  j ava 2s  .  co  m
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JPanel {

  public void paint(Graphics g) {
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;

    GradientPaint gp1 = new GradientPaint(5, 5, Color.red, 20, 20, Color.yellow, true);
    
    gp1.createContext(ColorModel.getRGBdefault(), new Rectangle(0,0,30,40), new Rectangle(0,0,30,40), 
        new AffineTransform(), null);
    
    System.out.println(gp1.getTransparency());
    g2d.setPaint(gp1);
    g2d.fillRect(20, 20, 300, 40);

  }

  public static void main(String[] args) {

    JFrame frame = new JFrame("GradientsRedYellow");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new Main());
    frame.setSize(350, 350);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}