每个段落带有NSTextContainer的NSLayoutManager

Question

How do I make an NSLayoutManager that assigns each paragraph in its text to a different NSTextContainer?

This would be similar to the multiple page/column usage that is common in TextKit, but each page corresponds to a different paragraph of variable length.

Answer 1

I think the easiest way to do this is to subclass NSTextContainer and override

- (CGRect)lineFragmentRectForProposedRect:(CGRect)proposedRect atIndex:(NSUInteger)characterIndex writingDirection:(NSWritingDirection)baseWritingDirection remainingRect:(CGRect *)remainingRect

In your custom method, you'd inspect the attributes at characterIndex and see if they matched the paragraph that text container is assigned to. If they are, just return super 's implementation of the method, otherwise return CGRectZero to signify that the proposed rect is invalid for this text container. This does mean you'll have to track paragraph attributes and the text containers they correlate to (and vice versa).

Answer 2

另一种方法是在每个段落的末尾插入分页符控制字符（ASCII代码：12）。