"disp" - mkraska/meclib Wiki
[ "disp", "name", [x,y], angle, offset, length]
small red arrow with label (indication of displacement). Same as dir, except for the color.
"name"
label, typeset in MathJax math mode[x,y]
start pointangle
arrow direction, counter-clockwise from x-axis, in °.offset
(optional, defaults to 10 pixels) distance from arrow to text anchor point in pixels. Ifoffset
< 0, then the label is placed at the tail of the arrow, otherwise at the head.length
(optional, defaults to equivalent of 24 pixels), in standard grid units
[
[ "grid", "x","y", -5,5,-4,5, 50, [1,1], [0,0] ],
[ "disp", "name", [2,1], 45, 10, 2],
[ "point", "start point", [2,1] ]
]