Determine how many characters in UILabel has truncated

Question

I have an UILabel and I want to determine how many characters in UILabel has truncated.
With this code below, I can determine it if my UILabel only have 1 line

int numberOfTruncatedCharacter = 0;
NSString *text = @"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s";

NSArray  *words = [text componentsSeparatedByString:@" "];
NSString *newStr = @"";
for (NSString *word in words) {
    NSString *statement = [NSString stringWithFormat:@"%@ %@",newStr, word];
    CGSize size = [statement sizeWithAttributes:@{NSFontAttributeName: self.aboutLabel.font}];

    if(size.width < self.aboutLabel.bounds.size.width){
        newStr = [NSString stringWithFormat:@"%@ %@",newStr, word];
    }else{
        numberOfTruncatedCharacter++;
    }
    NSLog(@"%@ | %f | %f",word,size.width,self.aboutLabel.bounds.size.width);
}
NSLog(@"number of truncated character = %d",numberOfTruncatedCharacter);

It works correctly and here is the log

2016-05-27 10:02:44.642 EarCrush[2284:42690] Lorem | 32.622070 | 355.000000
2016-05-27 10:02:44.642 EarCrush[2284:42690] Ipsum | 64.345703 | 355.000000
2016-05-27 10:02:44.642 EarCrush[2284:42690] is | 74.243164 | 355.000000
2016-05-27 10:02:44.643 EarCrush[2284:42690] simply | 107.138672 | 355.000000
2016-05-27 10:02:44.643 EarCrush[2284:42690] dummy | 145.644531 | 355.000000
2016-05-27 10:02:44.643 EarCrush[2284:42690] text | 165.952148 | 355.000000
2016-05-27 10:02:44.644 EarCrush[2284:42690] of | 177.978516 | 355.000000
2016-05-27 10:02:44.644 EarCrush[2284:42690] the | 195.854492 | 355.000000
2016-05-27 10:02:44.645 EarCrush[2284:42690] printing | 235.004883 | 355.000000
2016-05-27 10:02:44.646 EarCrush[2284:42690] and | 255.429688 | 355.000000
2016-05-27 10:02:44.647 EarCrush[2284:42690] typesetting | 309.921875 | 355.000000
2016-05-27 10:02:44.648 EarCrush[2284:42690] industry. | 353.134766 | 355.000000
2016-05-27 10:02:44.649 EarCrush[2284:42690] Lorem | 385.756836 | 355.000000
2016-05-27 10:02:44.649 EarCrush[2284:42690] Ipsum | 384.858398 | 355.000000
2016-05-27 10:02:44.650 EarCrush[2284:42690] has | 372.202148 | 355.000000
2016-05-27 10:02:44.650 EarCrush[2284:42690] been | 379.218750 | 355.000000
2016-05-27 10:02:44.650 EarCrush[2284:42690] the | 371.010742 | 355.000000
2016-05-27 10:02:44.651 EarCrush[2284:42690] industry's | 401.171875 | 355.000000
2016-05-27 10:02:44.651 EarCrush[2284:42690] standard | 397.431641 | 355.000000
2016-05-27 10:02:44.652 EarCrush[2284:42690] dummy | 391.640625 | 355.000000
2016-05-27 10:02:44.652 EarCrush[2284:42690] text | 373.442383 | 355.000000
2016-05-27 10:02:44.653 EarCrush[2284:42690] ever | 375.844727 | 355.000000
2016-05-27 10:02:44.653 EarCrush[2284:42690] since | 379.541016 | 355.000000
2016-05-27 10:02:44.653 EarCrush[2284:42690] the | 371.010742 | 355.000000
2016-05-27 10:02:44.654 EarCrush[2284:42690] 1500s | 383.374023 | 355.000000
2016-05-27 10:02:44.654 EarCrush[2284:42690] number of truncated character = 13

The problem is when my UILabel have multiple lines, I change my code to

if(size.width < self.aboutLabel.bounds.size.width * numberOfLines){

However it won't calculate correctly. I think maybe when UILabel have multiple lines, it will contains break line character

Any idea to fix it. Any help or suggestion would be great appreciated.

Answer 1

You are checking the width but you need to check the height.

Check out this open source and see how TTTAttributedLabel is using CoreText to know when to add the '...' character.

https://github.com/TTTAttributedLabel/TTTAttributedLabel/blob/master/TTTAttributedLabel/TTTAttributedLabel.m

Look at the drawframesetter:attributedstring:textrange:inrect:context: method

You can also change the open source and expose the position of '...'