在cairo中，也有画笔形状的概念，这由笔画宽度来表达。

With Cairo there is also a notion of a brush tip expressed through the stroke width.

youdao

大概的公式为：初始周框会根据画笔宽度膨胀，而这个结果是乘以斜接限制，加上某些要考虑端点的额外边界。

The approximate formula is: the initial bounding rectangle is inflated by pen width, and this result is multiplied by the miter limit, plus some additional margin to allow for end caps.

youdao

大概的公式为：初始周框会根据画笔宽度膨胀，而这个结果是乘以斜接限制，加上某些要考虑端点的额外边界。

The approximate formula is: the initial bounding rectangle is inflated by pen width, and this result is multiplied by the miter limit, plus some additional margin to allow for end caps.

youdao