A path can be drawn either as a solid line or with a dash pattern. Select the Solid Line button for a solid line or select the Dashed Line button for a dash pattern. The latter will enable the Offset, Dash and Gap fields. The offset is the distance from the starting vertex of the path to the start of the first dash. The dash pattern will then repeat line and gap pairs, where the line length is given by the Dash field and the gap length is given by the Gap field.
A dash-dot pattern can be obtained by selecting the Secondary checkbox and entering the secondary dash length and gap length. For example, in Figure 9.1 path (a) has a solid line; path (b) has a dash pattern with an offset of 0bp, dash length of 10bp and gap length of 5bp; path (c) is the same as path (b) except that the dash pattern has an offset of 10bp; path (d) has no offset, a primary pair of dash length 10bp and gap length 5bp, and a secondary pair of dash length 1bp and gap length 5bp which gives a dash-dot pattern.