参考

UIKIT_STATIC_INLINE CGRect UIEdgeInsetsInsetRect(CGRect rect, UIEdgeInsets insets) {
    rect.origin.x    += insets.left;
    rect.origin.y    += insets.top;
    rect.size.width  -= (insets.left + insets.right);
    rect.size.height -= (insets.top  + insets.bottom);
    return rect;
}

例子

CGRect rect = UIEdgeInsetsInsetRect(self.bounds, self.textContainerInset);