Hi Amine,
Firstly you can check how many characters are displayed for the width that you have in your smartform, please check by hardcoding first.
Then you can use the FM
CALL FUNCTION 'RKD_WORD_WRAP'
EXPORTING
textline = Text
delimiter = ' '
outputlen = no of characters
TABLES
out_lines = t_lines
EXCEPTIONS
outputlen_too_large = 1
OTHERS = 2.
with the delimiter as space. This will split into as many lines(with no of characters) based on ' ' as delimiter.
I hope this may solve your query.
Regards,
K.S