I use this to get line spacing.
;;; determine line spacing for a text style
(defun enco_line_space (t_style t_height / text_style text_height dot1 dot1_entity dot2 dot2_entity spacing)
(if (= t_style "")
(setq text_style (getvar "textstyle")) ; get the current text style
(setq text_style t_style)
)
(if (= t_height "")
(setq text_height (getvar "textsize")) ; get the current text height
(setq text_height t_height)
)
(entmake
(list
(cons 0 "MTEXT") ; Entity Type
(cons 100 "AcDbEntity") ; 100 Entity Code
(cons 100 "AcDbMText") ; 100 Entity Code
(cons 7 text_style)
(cons 8 "0")
(cons 40 text_height)
(cons 1 ".")
(cons 1 "\n.")
(cons 10 '(0.0 0.0 0.0)) ; Insertion Point
)
)
(command "explode" "last")
(setq dot1 (entlast)) ; get the entity
(setq dot1_entity (entget dot1)) ; get the entity's data
(entdel dot1) ; get rid of the evidence
(setq dot2 (entlast)) ; get the entity
(setq dot2_entity (entget dot2)) ; get the entity's data
(entdel dot2)
(setq dot1 (caddr (assoc 10 dot1_entity)))
(setq dot2 (caddr (assoc 10 dot2_entity)))
(setq spacing (- (caddr (assoc 10 dot2_entity)) (caddr (assoc 10 dot1_entity))))
spacing
)