UILabel negative line spacing - ios

Question

I've got a UILabel and I want to make the line spacing less than 0 (so the text moves closer together rather than further away). What am I doing wrong?
UIFont* customFont = [UIFont fontWithName:#"BebasNeue" size:70];
NSString * text = #"Their \nIdeas";
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:text];
NSMutableParagraphStyle *paragrahStyle = [[NSMutableParagraphStyle alloc] init];
paragrahStyle.lineSpacing = -30;
[attributedString addAttribute:NSParagraphStyleAttributeName value:paragrahStyle range:NSMakeRange(0, [text length])];
UILabel *lbl1 = [[UILabel alloc] init];
lbl1.frame = CGRectMake(120, 0, viewWidth, 300);
lbl1.backgroundColor = [UIColor clearColor];
lbl1.textColor = grayColor;
lbl1.numberOfLines = 2;
lbl1.attributedText = attributedString;
lbl1.userInteractionEnabled = NO;
lbl1.font = customFont;
[view addSubview:lbl1];
[lbl1 setTransform:CGAffineTransformMakeRotation(0.35)];

Answer 1

NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:labelText];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
CGFloat minMaxLineHeight = (font.pointSize - font.ascender + font.capHeight);
NSNumber *offset = #(font.capHeight - font.ascender);
NSRange range = NSMakeRange(0, labelText.length);
[style setMinimumLineHeight:minMaxLineHeight];
[style setMaximumLineHeight:minMaxLineHeight];
if (isCentered) {
[style setAlignment:NSTextAlignmentCenter];
}
[attrString addAttribute:NSParagraphStyleAttributeName
value:style
range:range];
[attrString addAttribute:NSBaselineOffsetAttributeName
value:offset
range:range];
This should get you near zero spacing on the text and should be safe to use with any font type and size.

Answer 2

Please see the following documentation from Apple setLineSpacing - NSMutableParagraphStyle , value must not be negative
setLineSpacing:
Sets the distance in points added between lines within the paragraph to aFloat.
- (void)setLineSpacing:(CGFloat)aFloat
Discussion
This value must be nonnegative.
There are also methods related to the minimum and maximum height for lines… probably setting line space to 0 and modifying the height could help you to achieve the effect you want-

Answer 3

Building off of Eric Murphey's answer, I've created an extension in Swift 4 syntax.
extension UILabel{
public func zeroLineSpace(){
let s = NSMutableAttributedString(string: self.text!)
let style = NSMutableParagraphStyle()
let lineHeight = self.font.pointSize - self.font.ascender + self.font.capHeight
let offset = self.font.capHeight - self.font.ascender
let range = NSMakeRange(0, self.text!.count)
style.maximumLineHeight = lineHeight
style.minimumLineHeight = lineHeight
style.alignment = self.textAlignment
s.addAttribute(.paragraphStyle, value: style, range: range)
s.addAttribute(.baselineOffset, value: offset, range: range)
self.attributedText = s
}
}
Simply call it like so
myUiLabel.zeroLineSpace()

Answer 4

Just a minor tweak to make things more configurable.
extension UILabel {
public func setLineHeight(lineHeight: CGFloat, textAlignment: NSTextAlignment ) {
guard let text = self.text else { return }
let attributeString = NSMutableAttributedString(string: text)
let styleLineHeight = self.font.pointSize - self.font.ascender + self.font.capHeight + lineHeight
let style = NSMutableParagraphStyle()
style.alignment = textAlignment
style.maximumLineHeight = styleLineHeight
style.minimumLineHeight = styleLineHeight
let offset = self.font.capHeight - self.font.ascender + lineHeight * 0.5
let range = NSMakeRange(0, text.count)
attributeString.addAttribute(.paragraphStyle, value: style, range: range)
attributeString.addAttribute(.baselineOffset, value: offset, range: range)
self.attributedText = attributeString
}
}

Answer 5

I cleaned up Christ Stillwell's answer a little bit:
extension UILabel {
public func zeroLineSpace() {
guard let text = self.text else { return }
let attributedString = NSMutableAttributedString(string: text)
let style = NSMutableParagraphStyle()
let lineHeight = self.font.pointSize - self.font.ascender + self.font.capHeight
let offset = self.font.capHeight - self.font.ascender
let range = NSRange(location: 0, length: attributedString.length)
style.maximumLineHeight = lineHeight
style.minimumLineHeight = lineHeight
style.alignment = self.textAlignment
attributedString.addAttribute(.paragraphStyle, value: style, range: range)
attributedString.addAttribute(.baselineOffset, value: offset, range: range)
self.attributedText = attributedString
}
}