Disable "..." truncating for a UITextField - ios

Question

I've been reviewing the documentation for UITextField and its options are much more limited than the UITextView.
I've run into a situation where I need to handle truncating the text by forcing the bounding box to be bigger so no truncation exists.
I cannot just use .adjustsFontSizeToFitWidth because this event is only allowed when the text box is at screen width. The truncation is happening when it's not full screen length.
Right now when the user types, I log each keystroke and make sure the UITextFields box expands to fit the text. However if I use a large font, the text is getting cut off still:
"THIS IS LARGE TEXT GETTING CUT O..."
Currently I log each keystroke and run this code to size it:
func adjustFrameWidthToFitText()
{
var size = sizeThatFits(CGSizeMake(CGFloat.max,height))
frame = CGRectMake(frame.origin.x, frame.origin.y, size.width + 7, frame.height)
}
However I still get the ... cut off in some places. Is there anyway to tell if the text is being truncated and override the behaviour causing said truncation?
(Solutions in Swift & Obj-c welcome!)
Based on the answer below I tried:
func adjustFrameWidthToFitText()
{
var fontSize = font.pointSize
var atr = [NSFontAttributeName:font]
var textSize = NSString(string: text).sizeWithAttributes(atr)
frame = CGRectMake(frame.origin.x, frame.origin.y, textSize.width, frame.height)
}
But there is still truncation

Answer 1

extension String {
func sizeWithAttributes(atr: NSDictionary) -> CGSize {
return NSString(string: self).sizeWithAttributes(atr)
}
}
let size = textView.text.sizeWithAttributes([NSFontAttribute:textView.font])
This will return the exact size for the string including '\n' characters.
The you can use the size however you want.
ADDED
Also when I was using CATextLayer I had to add this to the attributes to get the rows, havent tested on UITextView or field though:
let style = NSMutableParagraphStyle()
style.lineHeightMultiple = 1.05
..., NSParagraphStyleAttributeName:style])

Answer 2

After much digging I found the root cause, and a shortcut.
Shortcut first:
func adjustFrameWidthToFitText()
{
var size = intrinsicContentSize()
frame = CGRectMake(frame.origin.x, frame.origin.y, size.width, frame.height)
}
This gives me the size of the textfield.
The problem with my code was I was calculating the resize event BEFORE the character was added to the text. So my bounds were always being calculated before the latest keystroke was added to the string.
When I changed my logic
public func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{
adjustFrameWidthToFitText()
return true
}
To
textFieldDidEndEditing(_:)
{
adjustFrameWidthToFitText()
}
It works.
Voila!