class Line extends DJComponent { dj int x1; dj int y1; dj int x2; dj int y2; x <= x1; x <= x2; y <= y1; y <= y2; x1 <= x+width; x2 <= x+width; y1 <= y+height; y2 <= y+height; }A line is specified by two points: (x1,y1) and (x2,y2). The constraints ensure that the line lies inside the layout area for the line.