iOS14 上 UILabel 中显示的 NSAttributedString 错误

Question

具有某些属性的 NSMutableAttributedString 在 iOS 12 之前已正确显示在 UILabel 中，但 wrong/different 在 iOS 14:

字符串 "bukskin" 有两个红色字母，最后 4 个字母有下划线，正确 iOS 12:

在 iOS 14 上，下划线超出单词末尾大约两个字母。这似乎只有在下划线位于字符串末尾时才会发生：

iOS 12 和 iOS 14 的字符串属性转储看起来相同，但字符串在 iOS 14 的 UILabel 屏幕上显示不同。我错过了吗什么东西？

转储 iOS 12（使用 enumerateAttributesInRange）：

word=bukskin attributed_word=b{
    NSColor = "UIExtendedSRGBColorSpace 0.8125 0 0 1";
    NSLigature = 0;
    NSUnderline = 0;
}uk{
    NSColor = "UIExtendedGrayColorSpace 0 1";
    NSLigature = 0;
    NSUnderline = 0;
}s{
    NSColor = "UIExtendedGrayColorSpace 0 1";
    NSLigature = 0;
    NSUnderline = 1;
}k{
    NSColor = "UIExtendedSRGBColorSpace 0.8125 0 0 1";
    NSLigature = 0;
    NSUnderline = 1;
}in{
    NSColor = "UIExtendedGrayColorSpace 0 1";
    NSLigature = 0;
    NSUnderline = 1;
} attrs={
    NSColor = "UIExtendedGrayColorSpace 0 1";
    NSLigature = 0;
    NSUnderline = 1;
}

iOS14 的转储：

word=bukskin attributed_word=b{
    NSColor = "UIExtendedSRGBColorSpace 0.8125 0 0 1";
    NSLigature = 0;
    NSUnderline = 0;
}uk{
    NSColor = "<UIDynamicSystemColor: 0x600003682440; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 0;
}s{
    NSColor = "<UIDynamicSystemColor: 0x600003682440; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 1;
}k{
    NSColor = "UIExtendedSRGBColorSpace 0.8125 0 0 1";
    NSLigature = 0;
    NSUnderline = 1;
}in{
    NSColor = "<UIDynamicSystemColor: 0x600003682440; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 1;
} attrs={
    NSColor = "<UIDynamicSystemColor: 0x600003682440; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 1;
}

Answer 1

Tarun Tyagi 评论中的 link 暗示了一个修复：将整个属性字符串的基线偏移设置为 0。这似乎有效。初始化后我现在做：

[att_word addAttribute:NSBaselineOffsetAttributeName value:[NSNumber numberWithInt:0] range:NSMakeRange(0, att_word.length)];

我会向 Apple 提交错误。

现在的属性转储是：

word=bukskin attributed_word=b{
    NSBaselineOffset = 0;
    NSColor = "UIExtendedSRGBColorSpace 0.8125 0 0 1";
    NSLigature = 0;
    NSUnderline = 0;
}uk{
    NSBaselineOffset = 0;
    NSColor = "<UIDynamicSystemColor: 0x600000506f00; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 0;
}s{
    NSBaselineOffset = 0;
    NSColor = "<UIDynamicSystemColor: 0x600000506f00; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 1;
}k{
    NSBaselineOffset = 0;
    NSColor = "UIExtendedSRGBColorSpace 0.8125 0 0 1";
    NSLigature = 0;
    NSUnderline = 1;
}in{
    NSBaselineOffset = 0;
    NSColor = "<UIDynamicSystemColor: 0x600000506f00; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 1;
} attrs={
    NSBaselineOffset = 0;
    NSColor = "<UIDynamicSystemColor: 0x600000506f00; name = labelColor>";
    NSLigature = 0;
    NSUnderline = 1;
}

iOS14 上 UILabel 中显示的 NSAttributedString 错误

NSAttributedString displayed in UILabel wrong on iOS14

nsattributedstring

uilabel

ios