Determines how the end of lines are drawn.
|The same as Gdk::CAP_BUTT for lines of non-zero width. For zero width lines, the final point on the line will not be drawn.
|The ends of the lines are drawn squared off and extending to the coordinates of the end point.
|The ends of the lines are drawn as semicircles with the diameter equal to the line width and centered at the end point.
|The ends of the lines are drawn squared off and extending half the width of the line beyond the end point.