sizeWithFont returns wrong heigth value

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sizeWithFont returns wrong heigth value

Hi! I've a little problem. I need a multiline text with a dynamic content, so i have to set a content of a UITextView via code. The problem is that the heigth returned by sizeWithFont:constrainedToSize:lineBreakMode: is not perfetc at all, is often smaller a little bit. Let see an example:


NSString *string1 = @"Hi to all!I've this question for you, and i hope you can help me";
CGSize maxSize = CGSizeMake(320.0, 1000.0);
UIFont *font = [UIFont fontWithName:@"Helvetica-Bold" size:20.0];
CGSize textSize = [[string1 sizeWithFont:font constrainedToSize:maxSize lineBreakMode:UILineBreakModeWordWrap];
NSLog(@"Frame at indexPath %d: heigth %f width %f", indexPath, textSize.width, textSize.width);
CGRect textViewFrame = CGRectMake(0.0, 0.0, textSize.width, textSize.height);
UITextView *aTextView = [[UITextView alloc] initWithFrame:textViewFrame];
aTextView.text = string1;
aTextView.font = [UIFont fontWithName:@"Helvetica-Bold" size:20.0];
aTextView.userInteractionEnabled = NO;

Then, string1 appears, but not at all. It seems that the aTextView is too short to contain all the words. Where's the problem?

MacBook Pro 2,4 Ghz 15,4", Mac OS X (10.5.3)

Posted on Jan 19, 2009 4:27 AM

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Answer 1

Jan 19, 2009 8:57 AM in response to McKracken

The problem you're having is UITextView may use margins, 22pt line spacing on your 20pt font, etc. There are a few variables beyond height and weight, so measuring the font height of the string, even when asking Quartz to measure it wrapped, won't yield the same result.

I think what you're trying to do is tell UITextView to be 320 pixels tall and then whatever height it likes. Since UITextView is a scrollable view, sizeToFit will allow for 0 by 0 which isn't too helpful. However, all UITextView does is wrap UILabel, so you can just go to UILabel directly. UILabel has a method textRectForBounds: that will tell you how much space your text will take.

Here is your example written using UILabel:

-----

NSString *string1 = @"Hi to all!I've this question for you, and i hope you can help me";
CGRect textSize = CGRectMake(0.0, 0.0, 320.0, FLT_MAX);
UIFont *font = \[UIFont fontWithName:@"Helvetica-Bold" size:20.0\];
UILabel *label = \[\[UILabel alloc\] init\];
label.lineBreakMode = UILineBreakModeWordWrap;
// Zero means infinite in this case
label.numberOfLines = 0;
label.font = font;
label.text = string1;
label.frame = \[label textRectForBounds:textSize limitedToNumberOfLines:0\];
NSLog(@"Frame at width %f height %f", label.frame.size.width, label.frame.size.height);

-----

Hope that helps,
Luke Chastain

Fixed Wiki markup by Luke Chastain

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