add_dimension

add_dimension 
-arrowLine {f_x f_y} 
-color s_color 
[ -font s_font ] 
-orient s_orientation 
-p1 {f_x f_y} 
-p2 {f_x f_y}

The add_dimension command adds a dimension annotation to the active window.

`-arrowLine` {f_x f_y}
	Specifies the coordinates for the first arrow endpoint as two space-delimited real numbers, enclosed in braces.
`-color` s_color	Specifies the color for the annotation as the color name (such as `blue`) or the hexadecimal representation of the color preceded by a pound sign (#). A list of colors and their hexadecimal equivalents can be found on http://eies.njit.edu/~walsh/rgb.html.
`-font` s_font	Specifies the font type as `Arial`, `Courier`, or `Times Roman`.
`-orient` s_orientation
	Specifies the orientation of the measurement as one of the following: `horiz` indicates the measurement is on the x-axis. `vert` indicates the measurement is on the y-axis. `allangle` indicates the measurement is between two angles on a diagonal. `area` indicates that an area is measured.
`-p1` {f_x f_y}	Specifies the x- and y-coordinates for the first endpoint as two space-delimited real numbers, enclosed in braces
`-p2` {f_x f_y}	Specifies the x- and y-coordinates for the second endpoint as two space-delimited real numbers, enclosed in braces