How can I compute the number of lines of a UILabel with a fixed width?

Question

How can I compute the number of lines of a UILabel with a fixed width and a given text ?

http://stackoverflow.com/questions/4172615/how-to-find-uilabels-number-of-lines — Sunkas, Mar 01 '13 at 15:40

score 39 · Accepted Answer · edited Dec 30 '13 at 15:45

39

This code assumes label has the desired text and its frame is already set to the desired width.

- (int)lineCountForLabel:(UILabel *)label {
    CGSize constrain = CGSizeMake(label.bounds.size.width, FLT_MAX);
    CGSize size = [label.text sizeWithFont:label.font constrainedToSize:constrain lineBreakMode:UILineBreakModeWordWrap];

    return ceil(size.height / label.font.lineHeight);
}

Update:

If all you want is to determine the required height for the label based on its text and current width, then change this to:

- (CGSize)sizeForLabel:(UILabel *)label {
    CGSize constrain = CGSizeMake(label.bounds.size.width, FLT_MAX);
    CGSize size = [label.text sizeWithFont:label.font constrainedToSize:constrain lineBreakMode:UILineBreakModeWordWrap];

    return size;
}

The returned size is the proper width and height to contain the label.

edited Dec 30 '13 at 15:45

Sid

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answered Mar 01 '13 at 15:58

rmaddy

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Your question asked about calculating the number of lines. Are you saying you really want the required height (in points)? – rmaddy Mar 01 '13 at 16:01
as you wrote the number of lines equals the height divided by the lineHeight. I actually wanted to know the number of lines in order to compute the correct height for my label while keeping the width fixed. – Alexis Mar 01 '13 at 16:07
4

constrainedToSize is deprecated since iOs 6.0 – Juraj Petrik May 28 '14 at 20:11
First working solution I found! – coolcool1994 Jan 26 '17 at 03:11

score 4 · Answer 2 · edited Nov 05 '13 at 20:12

First get the height of the label from the label size using constrainedSize

CGSize labelSize = [label.text sizeWithFont:label.font 
                            constrainedToSize:label.frame.size 
                                lineBreakMode:UILineBreakModeWordWrap];
CGFloat labelHeight = labelSize.height;

once you have the label height then check the number of lines with the font size where fontsize is the size you are using for your label. e.g it could be 10 or depending on your requirements

CGSize sizeOfText = [label.text sizeWithFont:label.font 
                        constrainedToSize:label.frame.size 
                            lineBreakMode:UILineBreakModeWordWrap];
int numberOfLines = sizeOfText.height / label.font.pointSize;

Dividing by the fontSize is great, thanks. – Dan Rosenstark Nov 05 '13 at 20:12 — Dan Rosenstark, Nov 05 '13 at 20:12

score -1 · Answer 3 · answered Mar 01 '13 at 15:41

-1

You can compute the vertical height necessary to display the string using the sizeWithFont:constrainedToSize: method on NSString. Given that size, you can resize the label to display the entire string.

answered Mar 01 '13 at 15:41

Charlie Price

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How can I compute the number of lines of a UILabel with a fixed width?

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