From Xojo Documentation
Specifies the options for drawing line joins (where line endings intersect in a shape).
|Butt||A squared-off ending that ends at the line boundary.|
|Round||A rounded ending that extends beyond the line boundary.|
|Square||A squared-off ending that extends beyond the line boundary.|
This example sets the line join to Round:
g.LineJoin = WebGraphics.LineJoinType.Round