Calculating UILabel Text Size

Question

I am drawing UILabels programmatically. They get their sizes from a database. So I cannot just use sizeToFit. I have already implemented a function that redraws UILabels with a passed ratio. So all I need to find is the text in UILabel from my view that would require the maximum ratio to redraw UILabels. So finally I need to do something like this:

    double ratio = 1.00;
    for (UILabel* labels in sec.subviews) {

        float widthLabel = labels.frame.size.width;
        float heightLabel = labels.frame.size.height;
        float heightText = //get the text height here
        float widthText = //get the text width here
        if (widthLabel < widthText) {
            ratio = MAX(widthText/widthLabel,ratio);
        }
        if (heightLabel < heightText) {
            ratio = MAX(heightText/heightLabel, ratio);
        }
    }
    //redraw UILabels with the given ratio here

So how can I get the height and width size of a text, as some of my text do not fit into the label I cannot simply use label bounds? I am using Xcode 5 and iOS 7.

Answer 1

All of the [NSString sizeWithFont...] methods are deprecated in iOS 7. Use this instead.

CGRect labelRect = [text
                    boundingRectWithSize:labelSize
                    options:NSStringDrawingUsesLineFragmentOrigin
                    attributes:@{
                     NSFontAttributeName : [UIFont systemFontOfSize:14]
                    }
                    context:nil];

Also see https://developer.apple.com/documentation/foundation/nsstring/1619914-sizewithfont.

UPDATE - example of boundingRectWithSize output

Per your comment I did a simple test. The code and output is below.

// code to generate a bounding rect for text at various font sizes
NSString *text = @"This is a long sentence. Wonder how much space is needed?";
for (NSNumber *n in @[@(12.0f), @(14.0f), @(18.0f)]) {
    CGFloat fontSize = [n floatValue];
    CGRect r = [text boundingRectWithSize:CGSizeMake(200, 0)
                                  options:NSStringDrawingUsesLineFragmentOrigin
                               attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}
                                  context:nil];
    NSLog(@"fontSize = %f\tbounds = (%f x %f)",
          fontSize,
          r.size.width,
          r.size.height);
}

this produces the following output (note that the bounds change as expected as the font size gets larger):

fontSize = 12.000000    bounds = (181.152008 x 28.632000)
fontSize = 14.000000    bounds = (182.251999 x 50.105999)
fontSize = 18.000000    bounds = (194.039993 x 64.421997)