Adding any value for NSUnderlineStyleAttributeName causes NSParagraphStyle lineSpacing to be ignored

[bsmith11]

Using ASTextNode, adding any value for NSUnderlineStyleAttributeName causes the lineSpacing value to be ignored in NSParagraphStyleAttributeName value objects. I have tested this using UILabel and it works correctly. Using ADK 1.9.3. Example:

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineSpacing = 10.0f;
NSDictionary *attributes = @{NSForegroundColorAttributeName:[UIColor blackColor],
                             NSFontAttributeName:[UIFont systemFontOfSize:14.0f],
                             NSParagraphStyleAttributeName:paragraphStyle};
NSMutableAttributedString *mutableAttributedString = [[NSMutableAttributedString alloc] initWithString:@"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book."
                                                                                            attributes:attributes];

[mutableAttributedString addAttribute:NSUnderlineStyleAttributeName 
                                value:@(NSUnderlineStyleSingle)
                                range:NSMakeRange(10, 10)];

self.textNode.attributedString = mutableAttributedString;

[samhsiung]

might be an issue with ASCleanseAttributedStringOfCoreTextAttributes in ASTextKitCoreTextAdditions which scrubs unsupported CoreText attributes.

[bsmith11]

That's definitely it, I just did some testing to confirm. I'm already removing/converting CoreText attributes prior to this, so I know that I don't have any in the attributes. So it looks like kCTUnderlineStyleAttributeName has the same value as NSUnderlineStyleAttributeName. This triggers the ASAttributeWithNameIsUnsupportedCoreTextAttribute method to return YES. This causes NSAttributedStringAttributesForCoreTextAttributes to be called which tries to cleanse my attributes of CoreText attributes. Same as underline, kCTParagraphStyleAttributeName has the same value as NSParagraphStyleAttributeName, which triggers the conversion method paragraphStyleWithCTParagraphStyle to pass in my NSParagraphStyle object casted as a CTParagraphStyleRef. Since its not actually the CoreText version, my custom values don't get transferred to the newly created NSParagraphStyle.

Seems like we could fix it by adding an additional check in NSAttributedStringAttributesForCoreTextAttributes to see if the paragraph style is actually a CTParagraphStyleRef. If that sounds good, I'll open a PR with the fix.

[appleguy]

@bsmith11 thanks a lot for BOTH the report - and the fix! Really, even just the report was a great contribution to us. Hope to see you around! (if you're in SF, feel free to come visit the new Pinterest building if you're curious)