iOS drawInRect:attributes 执行多行文本截断 [英] iOS drawInRect:attributes perform text truncation with multiple lines

问题描述

如何在带有尾部截断的矩形中绘制长文本字符串?我尝试将 drawInRect:withAttributes: 与 NSLineBreakByTruncatingTail 段落样式一起使用，但它始终将文本呈现在一行上.它仅使用 NSLineBreakByWordWrapping 和 NSLineBreakByCharWrapping 中断模式呈现多行文本，并且在使用此选项时没有截断.为了实现这一点，我需要在段落样式上设置任何属性吗?或者这只是不再受支持，在这种情况下，除了继续使用已弃用的方法之外，我看不到其他选择.已弃用的方法 drawInRect:withFont:lineBreakMode:alignment: 工作正常.

How can I draw a long text string in a rect with tail truncation? I tried to use drawInRect:withAttributes: with NSLineBreakByTruncatingTail paragraph style, but it always renders text on a single line. It only renders multi-line text with NSLineBreakByWordWrapping and NSLineBreakByCharWrapping break modes and when using this option there is no truncation. Is there any property that I need to set on the paragraph style in order to make this happen? Or is this simply no longer supported, in which case I can see no alternative other than continuing to use deprecated methods. The deprecated method drawInRect:withFont:lineBreakMode:alignment:worked correctly.

推荐答案

这是可能的.

你是对的 - 你不能使用 NSLineBreakByTruncatingTail 段落样式，因为它只会显示单行截断的文本.

You are right - you can't use NSLineBreakByTruncatingTail paragraph style because it will show only single line of truncated text.

你应该使用 drawWithRect:options:attributes:context:

[string drawWithRect:CGRectMake(x, y, width, height)
             options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingTruncatesLastVisibleLine
          attributes:@{NSFontAttributeName:<font>, NSForegroundColorAttributeName:<color>}
             context:nil];

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