As trivial as it may sounds painting an arrow at the end of a line (of
arbitrary angle) isn't easy afterall. The line crosses vertically from
(0,0) to (Width, Height) of a TGraphicControl. Now the idea is to draw
a polygon (triangle) with (0,0) and (x1,y1), (x2,y2) the points of its
edges. How do you calculate these values. Assume an arraw
with top angle of 30 degrees.