How can I modify the gap between lines (line spacing) in a multiline UILabel
?
Edit: Evidently NSAttributedString
will do it, on iOS 6 and later. Instead of using an NSString
to set the label's text, create an NSAttributedString
, set attributes on it, then set it as the .attributedText
on the label. The code you want will be something like this:
NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:@"Sample text"];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
[style setLineSpacing:24];
[attrString addAttribute:NSParagraphStyleAttributeName
value:style
range:NSMakeRange(0, strLength)];
uiLabel.attributedText = attrString;
NSAttributedString's old attributedStringWithString did the same thing, but now that is being deprecated.
For historical reasons, here's my original answer:
Short answer: you can't. To change the spacing between lines of text, you will have to subclass UILabel
and roll your own drawTextInRect
, create multiple labels, or use a different font (perhaps one edited for a specific line height, see Phillipe's answer).
Long answer: In the print and online world, the space between lines of text is known as "leading" (rhymes with 'heading', and comes from the lead metal used decades ago). Leading is a read-only property of UIFont
, which was deprecated in 4.0 and replaced by lineHeight
. As far as I know, there's no way to create a font with a specific set of parameters such as lineHeight
; you get the system fonts and any custom font you add, but can't tweak them once installed.
There is no spacing parameter in UILabel
, either.
I'm not particularly happy with UILabel
's behavior as is, so I suggest writing your own subclass or using a 3rd-party library. That will make the behavior independent of your font choice and be the most reusable solution.
I wish there was more flexibility in UILabel
, and I'd be happy to be proven wrong!
Starting in ios 6 you can set an attributed string in the UILabel:
NSString *labelText = @"some text";
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle setLineSpacing:40];
[attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
cell.label.attributedText = attributedString ;
AttributedString
disables for example label's text alignment, so you have to add it to the paragraph style.
You can control line spacing in the storyboard:
https://i.stack.imgur.com/w6TJN.gif
From Interface Builder:
https://i.stack.imgur.com/UmKYm.gif
Programmatically:
SWift 4
Using label extension
extension UILabel {
func setLineSpacing(lineSpacing: CGFloat = 0.0, lineHeightMultiple: CGFloat = 0.0) {
guard let labelText = self.text else { return }
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = lineSpacing
paragraphStyle.lineHeightMultiple = lineHeightMultiple
let attributedString:NSMutableAttributedString
if let labelattributedText = self.attributedText {
attributedString = NSMutableAttributedString(attributedString: labelattributedText)
} else {
attributedString = NSMutableAttributedString(string: labelText)
}
// Line spacing attribute
attributedString.addAttribute(NSAttributedStringKey.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attributedString.length))
self.attributedText = attributedString
}
}
Now call extension function
let label = UILabel()
let stringValue = "How to\ncontrol\nthe\nline spacing\nin UILabel"
// Pass value for any one argument - lineSpacing or lineHeightMultiple
label.setLineSpacing(lineSpacing: 2.0) . // try values 1.0 to 5.0
// or try lineHeightMultiple
//label.setLineSpacing(lineHeightMultiple = 2.0) // try values 0.5 to 2.0
Or using label instance (Just copy & execute this code to see result)
let label = UILabel()
let stringValue = "Set\nUILabel\nline\nspacing"
let attrString = NSMutableAttributedString(string: stringValue)
var style = NSMutableParagraphStyle()
style.lineSpacing = 24 // change line spacing between paragraph like 36 or 48
style.minimumLineHeight = 20 // change line spacing between each line like 30 or 40
// Line spacing attribute
attrString.addAttribute(NSAttributedStringKey.paragraphStyle, value: style, range: NSRange(location: 0, length: stringValue.characters.count))
// Character spacing attribute
attrString.addAttribute(NSAttributedStringKey.kern, value: 2, range: NSMakeRange(0, attrString.length))
label.attributedText = attrString
Swift 3
let label = UILabel()
let stringValue = "Set\nUILabel\nline\nspacing"
let attrString = NSMutableAttributedString(string: stringValue)
var style = NSMutableParagraphStyle()
style.lineSpacing = 24 // change line spacing between paragraph like 36 or 48
style.minimumLineHeight = 20 // change line spacing between each line like 30 or 40
attrString.addAttribute(NSParagraphStyleAttributeName, value: style, range: NSRange(location: 0, length: stringValue.characters.count))
label.attributedText = attrString
My solution was to patch the font file itself and fix its line height definitely. http://mbauman.net/geek/2009/03/15/minor-truetype-font-editing-on-a-mac/
I had to modify 'lineGap', 'ascender', 'descender' in the 'hhea' block (as in the blog example).
This guy created a class to get line-height (without using CoreText, as MTLabel library) : https://github.com/LemonCake/MSLabel
Best thing I found is: https://github.com/mattt/TTTAttributedLabel
It's a UILabel subclass so you can just drop it in, and then to change the line height:
myLabel.lineHeightMultiple = 0.85;
myLabel.leading = 2;
I've found 3rd Party Libraries Like this one:
https://github.com/Tuszy/MTLabel
To be the easiest solution.
Here's some swift-code for you to set the line spacing programmatically
let label = UILabel()
let attributedText = NSMutableAttributedString(string: "Your string")
let paragraphStyle = NSMutableParagraphStyle()
//SET THIS:
paragraphStyle.lineSpacing = 4
//OR SET THIS:
paragraphStyle.lineHeightMultiple = 4
//Or set both :)
let range = NSMakeRange(0, attributedText.length)
attributedText.addAttributes([NSParagraphStyleAttributeName : paragraphStyle], range: range)
label.attributedText = attributedText
Of course, Mike's answer doesn't work if you pass the string programmatically. In this case you need to pass a attributed string and change it's style.
NSMutableAttributedString * attrString = [[NSMutableAttributedString alloc] initWithString:@"Your \nregular \nstring"];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
[style setLineSpacing:4];
[attrString addAttribute:NSParagraphStyleAttributeName
value:style
range:NSMakeRange(0, attrString.length)];
_label.attributedText = attrString;
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