textMetrics.m

+ (CGFloat)widthForAttributedString:(NSAttributedString *)text maxHeight:(CGFloat)maxHeight {
    CGSize size = [self sizeForAttributedString:text maxSize:CGSizeMake(CGFLOAT_MAX, maxHeight)];
    return size.width;
}

+ (CGFloat)widthForString:(NSString *)text font:(UIFont *)font maxHeight:(CGFloat)maxHeight {
    CGSize size = [self sizeForString:text font:font maxSize:CGSizeMake(CGFLOAT_MAX, maxHeight)];
    return size.width;
}

+ (CGFloat)heightForAttributedString:(NSAttributedString *)text maxWidth:(CGFloat)maxWidth {
    CGSize size = [self sizeForAttributedString:text maxSize:CGSizeMake(maxWidth, CGFLOAT_MAX)];
    return size.height;
}

+ (CGFloat)heightForString:(NSString *)text font:(UIFont *)font maxWidth:(CGFloat)maxWidth {
    CGSize size = [self sizeForString:text font:font maxSize:CGSizeMake(maxWidth, CGFLOAT_MAX)];
    return size.height;
}

+ (CGSize)sizeForAttributedString:(NSAttributedString *)text maxSize:(CGSize)maxSize {
    if (![text isKindOfClass:[NSAttributedString class]] || !text.length) {
        // no text means no height
        return CGSizeMake(0.0f, 0.0f);
    }
    
    NSStringDrawingOptions options = NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading;
    CGSize size = [text boundingRectWithSize:maxSize options:options context:nil].size;
    CGSize paddedSize = CGSizeMake(size.width + 1, size.height + 1);
    
    return paddedSize;
}

+ (CGSize)sizeForString:(NSString *)text font:(UIFont *)font maxSize:(CGSize)maxSize {
    if (![text isKindOfClass:[NSString class]] || !text.length) {
        // no text means no height
        return CGSizeMake(0.0f, 0.0f);
    }
    
    NSStringDrawingOptions options = NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading;
    NSDictionary *attributes = @{ NSFontAttributeName : font };
    CGSize size = [text boundingRectWithSize:maxSize options:options attributes:attributes context:nil].size;
    CGSize paddedSize = CGSizeMake(size.width + 1, size.height + 1);
    
    return paddedSize;
}