Calculate a Label size based on its content and a width. It is really useful when you wants to calculate a cell's height from its NSString label's content.

NSString+LabelSize.h

//--------------------------------------------------------
// 
//--------------------------------------------------------
// Project     : 
// File        : NSString+LabelSize.h
// Created     : $ 11/06/12 $
// Maintainer  : $ Rémi LAVEDRINE $
//
// Copyright Rémi LAVEDRINE 2004-2012, All Rights Reserved
//
// This software is the confidential and proprietary
// information of Rémi LAVEDRINE.
// You shall not disclose such Confidential Information
// and shall use it only in accordance with the terms
// of the license agreement you entered into with
// Rémi LAVEDRINE.
//--------------------------------------------------------
// 
// @brief
// Calculate a Label size based on its content and a width.
// It is really useful when you wants to calculate a cell's height from its NSString label's content.
//

#import <Foundation/Foundation.h>


//! @brief Calculate a Label size based on its content and a width.
//! @class NSString+LabelSize
//! @ingroup Utilities
//! @author Rémi Lavedrine
@interface NSString (LabelSize)

- (CGFloat)getTextHeightAtFont:(UIFont*)font forWidth:(CGFloat)width;

@end

NSString+LabelSize.m

//
//  NSString+LabelSize.m
//  
//
//  Created by Rémi LAVEDRINE on 11/06/12.
//  Copyright (c) 2012 Rémi LAVEDRINE. All rights reserved.
//

#import "NSString+LabelSize.h"

@implementation NSString (LabelSize)

/**
 @brief Get the height of a text based on its font. 
 @author : Rémi Lavedrine
 @date : 11/06/2012
 @remarks : <#(optional)#>
 */
- (CGFloat)getTextHeightAtFont:(UIFont*)font forWidth:(CGFloat)width{
  CGSize size = CGSizeMake(width, 1000);// here is the trick.
  CGSize textSize = [self sizeWithFont:font constrainedToSize:size];
  
  return textSize.height;
}

@end