Java tutorial
import java.awt.Graphics; import java.awt.image.BufferedImage; import javax.swing.JComponent; import javax.swing.JFrame; public class Main extends JComponent { public void paint(Graphics g) { int width = getSize().width; int height = getSize().height; int[] data = new int[width * height]; int i = 0; for (int y = 0; y < height; y++) { int red = (y * 255) / (height - 1); for (int x = 0; x < width; x++) { int green = (x * 255) / (width - 1); int blue = 128; data[i++] = (red << 16) | (green << 8) | blue; } } BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); image.setRGB(0, 0, width, height, data, 0, width); g.drawImage(image, 0, 0, this); } public static void main(String[] args) { JFrame frame = new JFrame("ColorPan"); frame.getContentPane().add(new Main()); frame.setSize(300, 300); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } }