An off-topic question regarding basic Java Programming

[tr4nquility]

It works ^^ Thanks Itaru

It seems that all kinds of drawing activities must be done inside paintComponent, and the listeners are meant to provide data necessary for drawing... Am I right ?

Would you please explain what this piece of code do ? (I know that it is another way to write "if" statement, but what is the logic behind this ?)

Code:

int x = (start.x < end.x) ? start.x : end.x;
int y = (start.y < end.y) ? start.y : end.y;
panel.repaint(x, y, Math.abs(start.x - end.x) + 1, Math.abs(start.y - end.y) + 1);

*Edit : I've managed to find my mistake... Before, I only call repaint(). It should be panel.repaint().... And then we must set a flag so that the paintComponent will fill the rectangle just once. This way, when mouseMoved() calls panel.repaint() , only the line is drawn. The rectangle is not refilled again.