DrawingCanvasBezier.java

public class DrawingCanvasBezier extends Component {

    GeneralPath p = new GeneralPath();
    int strokeColor = 0x0000ff;
    int strokeWidth = 10;

    private float lastX = -1;
    private float lastY = -1;

    private boolean odd=true;
    public void addPoint(float x, float y){
        if ( lastX == -1 ){
            p.moveTo(x, y);

        } else {
            float controlX = odd ? lastX : x;
            float controlY = odd ? y : lastY;
            p.quadTo(controlX, controlY, x, y);
        }
        odd = !odd;
        lastX = x;
        lastY = y;
        repaint();
    }

    @Override
    protected void paintBackground(Graphics g) {
        super.paintBackground(g);
        Stroke stroke = new Stroke(
                strokeWidth,
                Stroke.CAP_BUTT,
                Stroke.JOIN_ROUND, 1f
        );
        g.setColor(strokeColor);

        // Draw the shape
        g.drawShape(p, stroke);

    }

    @Override
    public void pointerPressed(int x, int y) {
        addPoint(x-getParent().getAbsoluteX(), y-getParent().getAbsoluteY());
    }

}