Drawing with the Graphics Class

The Graphics Context

Every paint operation goes through the abstract Graphics class. Override paint(Graphics g) and use its drawing methods to draw on a component such as a Canvas.

Drawing Shapes

import java.awt.*;

class ShapeCanvas extends Canvas {
    public void paint(Graphics g) {
        g.setColor(Color.RED);
        g.drawLine(20, 20, 200, 20);
        g.drawRect(20, 50, 120, 80);
        g.fillOval(170, 50, 100, 80);
        g.drawString("Hello Graphics", 30, 180);
    }
}

Add the canvas to a Frame, and every window redraw calls paint() again.

Key Points

• paint(Graphics) is called automatically when the component needs drawing.
• graphics are non-persistent: requests repaint() to redraw after changes.
• All colors, fonts and text also go through the Graphics object.