The Line and Box style sets attributes of subsequent lines and boxes.
The properties are these:
Stroke
The width of the lines used. This is measured in whatever measurement you have chosen, so usually this will not be a whole number but rather e.g. 0.05 or simular.
Box corner rounding (circle radius)
The radius of the circle for which a circle arc is used as a corner. Specify 0 for a sharp corner, or the radius of the circle for a round corner.
Notice: Round corners are not supported for ZPL/DP output. Any rounded corners are in ZPL and DP printed as sharp.
Box fill
Set this to ‘On’ if you want to fill out the inside of the boxes inserted after the style.