Get NSTextField contents to scale

Question

How can I have the text scale to fit the bounds I gave it?

Answer 1

I've done something like this in the past.

-(void)calcFontSizeToFitRect:(NSRect)r {
    float targetWidth = r.size.width - xMargin;
    float targetHeight = r.size.height - yMargin;
    
    // the strategy is to start with a small font size and go larger until I'm larger than one of the target sizes
    int i;
    for (i=minFontSize; i<maxFontSize; i++) {
        NSDictionary* attrs = [[NSDictionary alloc] initWithObjectsAndKeys:[NSFont fontWithName:currentFontName size:i], NSFontAttributeName, nil];
        NSSize strSize = [stringValue sizeWithAttributes:attrs];
        [attrs release];
        if (strSize.width > targetWidth || strSize.height > targetHeight) break;
    }
    [self setCurrentFontSize:(i-1)];
}

The stringValue variable is the text you want sized. The xMargin and yMargin variables are for spacing that you want. The minFontSize and maxFontSize variables give limits to how small or large you want to go.

Answer 2

This solution appropriated from iOS works quite well. However, one thing to note: If you are setting this up programatically, you need to initialise your NSTextfield with a rect that has a width and height, otherwise the bounds returns 0.

Also here's the link where I found this solution: https://medium.com/@joncardasis/dynamic-text-resizing-in-swift-3da55887beb3

extension NSFont {
  /**
   Will return the best font conforming to the descriptor which will fit in the provided bounds.
   */
  static func bestFittingFontSize(for text: String, in bounds: CGRect, fontDescriptor: NSFontDescriptor, additionalAttributes: [NSAttributedString.Key: Any]? = nil) -> CGFloat {
    let constrainingDimension = min(bounds.width, bounds.height)
    let properBounds = CGRect(origin: .zero, size: bounds.size)
    var attributes = additionalAttributes ?? [:]

    let infiniteBounds = CGSize(width: CGFloat.infinity, height: CGFloat.infinity)
    var bestFontSize: CGFloat = constrainingDimension

    for fontSize in stride(from: bestFontSize, through: 0, by: -1) {
      let newFont = NSFont(descriptor: fontDescriptor, size: fontSize)
      attributes[.font] = newFont

      let currentFrame = text.boundingRect(with: infiniteBounds, options: [.usesLineFragmentOrigin, .usesFontLeading], attributes: attributes, context: nil)

      if properBounds.contains(currentFrame) {
        bestFontSize = fontSize
        break
      }
    }
    return bestFontSize
  }

  static func bestFittingFont(for text: String, in bounds: CGRect, fontDescriptor: NSFontDescriptor, additionalAttributes: [NSAttributedString.Key: Any]? = nil) -> NSFont {
    let bestSize = bestFittingFontSize(for: text, in: bounds, fontDescriptor: fontDescriptor, additionalAttributes: additionalAttributes)
    // TODO: Safely unwrap this later
    return NSFont(descriptor: fontDescriptor, size: bestSize)!
  }
}

extension NSTextField {
  /// Will auto resize the contained text to a font size which fits the frames bounds.
  /// Uses the pre-set font to dynamically determine the proper sizing
  func fitTextToBounds() {
    guard let currentFont = font else {
      return
    }
    let text = stringValue
    let bestFittingFont = NSFont.bestFittingFont(for: text, in: bounds, fontDescriptor: currentFont.fontDescriptor, additionalAttributes: basicStringAttributes)
    font = bestFittingFont
  }

  private var basicStringAttributes: [NSAttributedString.Key: Any] {
    var attribs = [NSAttributedString.Key: Any]()

    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.alignment = self.alignment
    paragraphStyle.lineBreakMode = self.lineBreakMode
    attribs[.paragraphStyle] = paragraphStyle

    return attribs
  }
}

Answer 3

For me label.adjustsFontSizeToFitWidth = true reduces the font size. 

with...


lazy var labelContainerView: UIView =
{   let view = UIView()
    return  view.labelContainerView(view: view, label)   }()


extension UIView {
func anchor(   top: NSLayoutYAxisAnchor?,
                    left: NSLayoutXAxisAnchor?,
                    bottom: NSLayoutYAxisAnchor?,
                    right: NSLayoutXAxisAnchor?,
                    paddingTop: CGFloat,
                    paddingLeft: CGFloat,
                    paddingBottom: CGFloat,
                    paddingRight: CGFloat,
                    width: CGFloat,
                    height: CGFloat     )

    {   translatesAutoresizingMaskIntoConstraints = false

        if let top = top {   self.topAnchor.constraint(equalTo: top, constant: paddingTop).isActive = true   }

        if let left = left {   self.leftAnchor.constraint(equalTo: left, constant: paddingLeft).isActive = true   }

        if let bottom = bottom {   self.bottomAnchor.constraint(equalTo: bottom, constant: -paddingBottom).isActive = true   }

        if let right = right {   self.rightAnchor.constraint(equalTo: right, constant: -paddingRight).isActive = true   }

        if width != 0 {   widthAnchor.constraint(equalToConstant: width).isActive = true   }

        if height != 0 {   heightAnchor.constraint(equalToConstant: height).isActive = true    }
    }
}


func labelContainerView(view: UIView, _ label: UILabel) -> UIView

    {   view.addSubview(label)
        label.anchor(top: view.topAnchor, left: view.leftAnchor, bottom: nil, right: nil, paddingTop: 0, paddingLeft: 0, paddingBottom: 0, paddingRight: 0, width: 0, height: 0)
        label.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        label.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true

        return view
    }
}