public void keyPressed(KeyEvent e) {
.
.
.
switch(e.getKeyCode())
            {
                case KeyEvent.VK_UP:   // AUMENTAR O TAMANHO DO DESENHO
                    x1 += x1;
                    y1 += y1;
                        x2 += x2;
                        y2 += y2;
                    x3 += x3;
                    y3 += y3; break;

                case KeyEvent.VK_DOWN:  // DIMINUIR O TAMANHO DO DESENHO
                    x1 /= 2;
                    y1 /= 2;
                        x2 /= 2;
                        y2 /= 2;
                    x3 /= 2;
                    y3 /= 2; break;
            }