Multiline UILabel with adjustsFontSizeToFitWidth

Question

I have a multiline UILabel whose font size I\'d like to adjust depending on the text length. The whole text should fit into the label\'s frame without truncating it.

Answer 1

It seems to me that there is now a better answer to this question

I have discovered that the font size adjusts automatically on a multiline label when you set adjustsFontSizeToFitWidth true, numberOfLines 0, a minimumScaleFactor little enough to let the font shrink as needed, and the default lineBreakMode (byTruncatingTail)

PS: I cannot find anything about this change on the official documentation. I created a question to find out more informations on this topic here

Answer 2

In this question, 0x90 provides a solution that - although a bit ugly - does what I want. Specifically, it deals correctly with the situation that a single word does not fit the width at the initial font size. I've slightly modified the code so that it works as a category on NSString:

- (CGFloat)fontSizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size {
    CGFloat fontSize = [font pointSize];
    CGFloat height = [self sizeWithFont:font constrainedToSize:CGSizeMake(size.width,FLT_MAX) lineBreakMode:UILineBreakModeWordWrap].height;
    UIFont *newFont = font;

    //Reduce font size while too large, break if no height (empty string)
    while (height > size.height && height != 0) {   
        fontSize--;  
        newFont = [UIFont fontWithName:font.fontName size:fontSize];   
        height = [self sizeWithFont:newFont constrainedToSize:CGSizeMake(size.width,FLT_MAX) lineBreakMode:UILineBreakModeWordWrap].height;
    };

    // Loop through words in string and resize to fit
    for (NSString *word in [self componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]) {
        CGFloat width = [word sizeWithFont:newFont].width;
        while (width > size.width && width != 0) {
            fontSize--;
            newFont = [UIFont fontWithName:font.fontName size:fontSize];   
            width = [word sizeWithFont:newFont].width;
        }
    }
    return fontSize;
}

To use it with a UILabel:

    CGFloat fontSize = [label.text fontSizeWithFont:[UIFont boldSystemFontOfSize:15] constrainedToSize:label.frame.size];
    label.font = [UIFont boldSystemFontOfSize:fontSize];

EDIT: Fixed the code to initialize newFont with font. Fixes a crash under certain circumstances.

Answer 3

For a fully working solution, see the bottom of my answer

Answer 4

In some cases, changing "Line Breaks" from "Word Wrap" to "Truncate Tail" may be all you need, if you know how many lines you want (e.g. "2"): Credit: Becky Hansmeyer

Answer 5

There is an ObjC extension provided in comments, that calculate fontsize required to fit multiline text into UILabel. It was rewritten in Swift (since it is 2016):

//
//  NSString+KBAdditions.swift
//
//  Created by Alexander Mayatsky on 16/03/16.
//
//  Original code from http://stackoverflow.com/a/4383281/463892 & http://stackoverflow.com/a/18951386
//

import Foundation
import UIKit

protocol NSStringKBAdditions {
    func fontSizeWithFont(font: UIFont, constrainedToSize size: CGSize, minimumScaleFactor: CGFloat) -> CGFloat
}

extension NSString : NSStringKBAdditions {
    func fontSizeWithFont(font: UIFont, constrainedToSize size: CGSize, minimumScaleFactor: CGFloat) -> CGFloat {
        var fontSize = font.pointSize
        let minimumFontSize = fontSize * minimumScaleFactor


        var attributedText = NSAttributedString(string: self as String, attributes:[NSFontAttributeName: font])
        var height = attributedText.boundingRectWithSize(CGSize(width: size.width, height: CGFloat.max), options:NSStringDrawingOptions.UsesLineFragmentOrigin, context:nil).size.height

        var newFont = font
        //Reduce font size while too large, break if no height (empty string)
        while (height > size.height && height != 0 && fontSize > minimumFontSize) {
            fontSize--;
            newFont = UIFont(name: font.fontName, size: fontSize)!

            attributedText = NSAttributedString(string: self as String, attributes:[NSFontAttributeName: newFont])
            height = attributedText.boundingRectWithSize(CGSize(width: size.width, height: CGFloat.max), options:NSStringDrawingOptions.UsesLineFragmentOrigin, context:nil).size.height
        }

        // Loop through words in string and resize to fit
        for word in self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()) {
            var width = word.sizeWithAttributes([NSFontAttributeName:newFont]).width
            while (width > size.width && width != 0 && fontSize > minimumFontSize) {
                fontSize--
                newFont = UIFont(name: font.fontName, size: fontSize)!
                width = word.sizeWithAttributes([NSFontAttributeName:newFont]).width
            }
        }
        return fontSize;
    }
}

Link to full code: https://gist.github.com/amayatsky/e6125a2288cc2e4f1bbf

Answer 6

Thanks, with that and a little more from someone else I did this custom UILabel, that will respect the minimum font size and there's a bonus option to align the text to top.

h:

@interface EPCLabel : UILabel {
    float originalPointSize;
    CGSize originalSize;
}

@property (nonatomic, readwrite) BOOL alignTextOnTop;
@end

m:

#import "EPCLabel.h"

@implementation EPCLabel
@synthesize alignTextOnTop;

-(void)verticalAlignTop {
    CGSize maximumSize = originalSize;
    NSString *dateString = self.text;
    UIFont *dateFont = self.font;
    CGSize dateStringSize = [dateString sizeWithFont:dateFont 
                                   constrainedToSize:CGSizeMake(self.frame.size.width, maximumSize.height)
                                       lineBreakMode:self.lineBreakMode];

    CGRect dateFrame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, dateStringSize.height);

    self.frame = dateFrame;
}

- (CGFloat)fontSizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size {
    CGFloat fontSize = [font pointSize];
    CGFloat height = [self.text sizeWithFont:font             
                           constrainedToSize:CGSizeMake(size.width,FLT_MAX)  
                               lineBreakMode:UILineBreakModeWordWrap].height;
    UIFont *newFont = font;

    //Reduce font size while too large, break if no height (empty string)
    while (height > size.height && height != 0 && fontSize > self.minimumFontSize) { 
        fontSize--;  
        newFont = [UIFont fontWithName:font.fontName size:fontSize];   
        height = [self.text sizeWithFont:newFont  
                       constrainedToSize:CGSizeMake(size.width,FLT_MAX) 
                           lineBreakMode:UILineBreakModeWordWrap].height;
    };

    // Loop through words in string and resize to fit
    if (fontSize > self.minimumFontSize) {
        for (NSString *word in [self.text componentsSeparatedByString:@" "]) {
            CGFloat width = [word sizeWithFont:newFont].width;
            while (width > size.width && width != 0 && fontSize > self.minimumFontSize) {
                fontSize--;
                newFont = [UIFont fontWithName:font.fontName size:fontSize];   
                width = [word sizeWithFont:newFont].width;
            }
        }
    }
    return fontSize;
}

-(void)setText:(NSString *)text {
    [super setText:text];
    if (originalSize.height == 0) {
        originalPointSize = self.font.pointSize;
        originalSize = self.frame.size;
    }

    if (self.adjustsFontSizeToFitWidth && self.numberOfLines > 1) {
        UIFont *origFont = [UIFont fontWithName:self.font.fontName size:originalPointSize];
        self.font = [UIFont fontWithName:origFont.fontName size:[self fontSizeWithFont:origFont constrainedToSize:originalSize]];
    }

    if (self.alignTextOnTop) [self verticalAlignTop];
}

-(void)setAlignTextOnTop:(BOOL)flag {
    alignTextOnTop = YES;
    if (alignTextOnTop && self.text != nil)
        [self verticalAlignTop];
}

@end

I hope it helps.