quickly. A hairline pen is approximately 1/72 of an inch thick (this thickness is not guaranteed), and cannot have pen balance, cap styles, or joint styles. Cap styles or joint styles defined for a hairline pen are ignored. Cap and joint styles are described in the following headings.
NOTE
Hairline pens are intended for fast approximate rendering. Do not use a hairline pen when exact thickness is important such as in a user interface. Hairline pens can be inaccurate, and your elements may not line up properly. Always use a thick pen when accuracy is important.