Java: Images - BufferedImage

Java: Images - BufferedImage:

To create a BufferedImage

import java.awt.image.*;
. . .
class Painting extends JPanel {
   . . .
   BufferedImage grid;  // declare the image
   . . .
   public void paintComponent(Graphics g) {
       super.paintComponent(g);       // paint background
       Graphics2D g2 = (Graphics2D)g; // we need a Graphics2D context
  
       if (grid == null) {
           // Compute the grid only one time
           int w = this.getWidth();
           int h = this.getHeight();
           grid = (BufferedImage)(this.createImage(w,h));
           Graphics2D gc = grid.createGraphics();
           for (int x=0; x<w; x+=10) {gc.drawLine(x, 0, x, h);}
           for (int y=0; y<h; y+=10) {gc.drawLine(0, y, w, y);}
       }
       // Draw the grid from the precomputed image
       g2.drawImage(grid, null, 0, 0);
       . . . // draw remaining, dynamic, image