使用NSTextAttachment为NSAttributedString设置截尾的垂直对齐

问题描述

我正在使用以下代码在iOS 8中为 UILabel 生成 NSAttributedString 。

I'm using the following code to generate a NSAttributedString for UILabel in iOS 8.

// a long long Chinese title
NSString *title = @"这是一个很长很长很长很长很长很长的中文标题";
// setup icon attachment
NSTextAttachment *iconAttachment = [[NSTextAttachment alloc] init];
iconAttachment.image = [UIImage imageNamed:imageName];
iconAttachment.bounds = bounds;
NSAttributedString *ycardImageString = [NSAttributedString attributedStringWithAttachment:iconAttachment];

// setup attributed text
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithString:title];
if (shouldShowYcard) {
    [attributedText insertAttributedString:ycardImageString atIndex:0];
    [attributedText insertAttributedString:[[NSAttributedString alloc] initWithString:@" "] atIndex:1];
    [attributedText addAttribute:NSBaselineOffsetAttributeName value:@(offset) range:NSMakeRange(0, 1)];
}
NSRange titleRange = NSMakeRange(shouldShowYcard ? 2 : 0, title.length);
[attributedText addAttribute:NSFontAttributeName value:font range:titleRange];
[attributedText addAttribute:NSForegroundColorAttributeName value:color range:titleRange];

但是 NSTextAttachment 似乎会生效截尾的垂直位置，如下图所示。

However it seems that the NSTextAttachment will effect the vertical position of truncated tails, just like the following pictures.

有没有办法设置truncat的垂直高度

Is there a way to set the vertical aignment for the truncated tails?

我的目标是使中文尾巴对齐。

My goal is to have bottom align tails in Chinese language.

这是一个图标测试。

推荐答案

好，最后我选择了一种丑陋的方法来解决此问题 NSBaselineOffsetAttributeName 截尾。

OK, finally I choose a ugly way to fix this problem by setting NSBaselineOffsetAttributeName for truncate tail.

是一种计算截断部分的方法。但是对于我来说，我的标签宽度是固定的，因此我可以直接设置控制范围。

Here is a way to calculate the truncate part. But in my case, my label width is fixed so that I can directly set the range for control.

if (title.length > 10 && ([[[UIDevice currentDevice] systemVersion] floatValue] < 9.0)) {
    [attributedText addAttribute:NSBaselineOffsetAttributeName value:@(-4) range:NSMakeRange(9, 1)];
}

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