How to calculate the width of a text string of a specific font and font-size

Question

I have a UILabel that displays some chars  Like  x    y  or  rpm   How can I calculate the width of the text in the label  it does not ues the whole available space   This is for automatic layouting  where another view will have a bigger frame rectangle if that UILabel has a smaller text inside  Are there methods to calculate that width of the text when a UIFont and font size is specified  There s also no line-break and just one single line

User · Answer

Update Sept 2019

This answer is a much cleaner way to do it using new syntax.

Original Answer

Based on Glenn Howes' excellent answer, I created an extension to calculate the width of a string. If you're doing something like setting the width of a UISegmentedControl, this can set the width based on the segment's title string.

extension String {

    func widthOfString(usingFont font: UIFont) -> CGFloat {
        let fontAttributes = [NSAttributedString.Key.font: font]
        let size = self.size(withAttributes: fontAttributes)
        return size.width
    }

    func heightOfString(usingFont font: UIFont) -> CGFloat {
        let fontAttributes = [NSAttributedString.Key.font: font]
        let size = self.size(withAttributes: fontAttributes)
        return size.height
    }

    func sizeOfString(usingFont font: UIFont) -> CGSize {
        let fontAttributes = [NSAttributedString.Key.font: font]
        return self.size(withAttributes: fontAttributes)
    }
}

usage:

    // Set width of segmentedControl
    let starString = "??"
    let starWidth = starString.widthOfString(usingFont: UIFont.systemFont(ofSize: 14)) + 16
    segmentedController.setWidth(starWidth, forSegmentAt: 3)

User · Answer

sizeWithFont  is now deprecated  use sizeWithAttributes  instead   UIFont  font    UIFont fontWithName   Helvetica  size 30   NSDictionary  userAttributes     NSFontAttributeName  font                                   NSForegroundColorAttributeName   UIColor blackColor    NSString  text     hello       const CGSize textSize    text sizeWithAttributes  userAttributes

User · Answer

Since sizeWithFont is deprecated  I m just going to update my original answer to using Swift 4 and  size      Playground - noun  a place where people can play  import UIKit  if let font   UIFont name   Helvetica   size  24       let fontAttributes    NSAttributedStringKey font  font     let myText    Your Text Here     let size    myText as NSString  size withAttributes  fontAttributes      The size should be the onscreen size of  Your Text Here  in points

User · Answer

If you re struggling to get text width with multiline support  so you can use the next code  Swift 5    func width text  String  height  CGFloat  - gt  CGFloat       let attributes   NSAttributedString Key  Any               font  UIFont systemFont ofSize  17            let attributedText   NSAttributedString string  text  attributes  attributes      let constraintBox   CGSize width   greatestFiniteMagnitude  height  height      let textWidth   attributedText boundingRect with  constraintBox  options    usesLineFragmentOrigin   usesFontLeading   context  nil  width rounded  up       return textWidth     And the same way you could find text height if you need to  just switch the constraintBox implementation    let constraintBox   CGSize width  maxWidth  height   greatestFiniteMagnitude    Or here s a unified function to get text size with multiline support   func labelSize for text  String  maxWidth  CGFloat  maxHeight  CGFloat  - gt  CGSize       let attributes   NSAttributedString Key  Any               font  UIFont systemFont ofSize  17             let attributedText   NSAttributedString string  text  attributes  attributes       let constraintBox   CGSize width  maxWidth  height  maxHeight      let rect   attributedText boundingRect with  constraintBox  options    usesLineFragmentOrigin   usesFontLeading   context  nil  integral      return rect size     Usage   let textSize   labelSize for   SomeText   maxWidth  contentView bounds width  maxHeight   greatestFiniteMagnitude  let textHeight   textSize height rounded  up  let textWidth   textSize width rounded  up

User · Answer

This simple extension in Swift works well   extension String       func size OfFont font  UIFont  - gt  CGSize           return  self as NSString  size attributes   NSFontAttributeName  font             Usage   let string    hello world   let font   UIFont systemFont ofSize  12  let width   string size OfFont  font  width    size   w  98 912 h  14 32

User · Answer

You can do exactly that via the various sizeWithFont  methods in NSString UIKit Additions  In your case the simplest variant should suffice  since you don t have multi-line labels    NSString  someString     Hello World   UIFont  yourFont       UIFont      CGSize stringBoundingBox    someString sizeWithFont yourFont     There are several variations of this method  eg  some consider line break modes or maximum sizes

User · Answer

Swift 4  extension String       func SizeOf   font  UIFont  - gt  CGSize           return self size withAttributes   NSAttributedStringKey font  font

User · Answer

Not sure how efficient this is  but I wrote this function that returns the point size that will fit a string to a given width   func fontSizeThatFits targetWidth  CGFloat  maxFontSize  CGFloat  font  UIFont  - gt  CGFloat       var variableFont   font withSize maxFontSize      var currentWidth   self size withAttributes   NSAttributedString Key font variableFont   width      while currentWidth  gt  targetWidth           variableFont   variableFont withSize variableFont pointSize - 1          currentWidth   self size withAttributes   NSAttributedString Key font variableFont   width            return variableFont pointSize     And it would be used like this   textView font   textView font  withSize textView text  fontSizeThatFits targetWidth  view frame width  maxFontSize  50  font  textView font

User · Answer

Swift-5  Use intrinsicContentSize to find the text height and width    yourLabel intrinsicContentSize width  This will work even you have custom spacing between your string like  T E X T

User · Answer

This is for swift 2 3 Version  You can get the width of string   var sizeOfString   CGSize   if let font   UIFont name   Helvetica   size  14 0                let finalDate    Your Text Here          let fontAttributes    NSFontAttributeName  font     it says name  but a UIFont works         sizeOfString    finalDate as NSString  sizeWithAttributes fontAttributes

User · Answer

Oneliner in Swift 4 2   let size   text size withAttributes   font  UIFont systemFont ofSize 18 0

User · Answer

For Swift 3 0   extension String       func SizeOf String  font  UIFont  - gt  CGSize           let fontAttribute    NSFontAttributeName  font          let size   self size attributes  fontAttribute      for Single Line        return size           Use it like             let Str    ABCDEF          let Font    UIFont systemFontOfSize 19 0          let SizeOfString   Str SizeOfString font  Font

User · Answer

The way I am doing it my code is to make an extension of UIFont   This is Swift 4 1   extension UIFont         public func textWidth s  String  - gt  CGFloat               return s size withAttributes   NSAttributedString Key font  self   width             extension UIFont

[iphone] How to calculate the width of a text string of a specific font and font-size?

Update Sept 2019

Original Answer

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