The following code attempts to draw a black rectangle from (10, 20) to (50, 40) with a line across its diagonal:

DrawingPanel panel = new DrawingPanel(200, 100);

Graphics g = panel.getGraphics();

g.drawRect(10, 20, 50, 40);

g.drawLine(10, 20, 50, 40);

However, the graphical output looks like Figure 3G.20 instead. What must be changed for it to look as intended?

Drawing Panel