How to get height for NSAttributedString at a fixed width

user_93342 0
Viewed 31438

I want to do some drawing of NSAttributedStrings in fixed-width boxes, but am having trouble calculating the right height they'll take up when drawn. So far, I've tried:

  1. Calling - (NSSize) size, but the results are useless (for this purpose), as they'll give whatever width the string desires.

  2. Calling - (void)drawWithRect:(NSRect)rect options:(NSStringDrawingOptions)options with a rect shaped to the width I want and NSStringDrawingUsesLineFragmentOrigin in the options, exactly as I'm using in my drawing. The results are ... difficult to understand; certainly not what I'm looking for. (As is pointed out in a number of places, including this Cocoa-Dev thread).

  3. Creating a temporary NSTextView and doing:
    [[tmpView textStorage] setAttributedString:aString];
    [tmpView setHorizontallyResizable:NO];
    [tmpView sizeToFit];
    When I query the frame of tmpView, the width is still as desired, and the height is often correct ... until I get to longer strings, when it's often half the size that's required. (There doesn't seem to be a max size being hit: one frame will be 273.0 high (about 300 too short), the other will be 478.0 (only 60-ish too short)).

I'd appreciate any pointers, if anyone else has managed this.

nstextview appkit nsattributedstring cocoa
12 Answers
-[NSAttributedString boundingRectWithSize:options:]

You can specify NSStringDrawingUsesDeviceMetrics to get union of all glyph bounds.

Unlike -[NSAttributedString size], the returned NSRect represents the dimensions of the area that would change if the string is drawn.

As @Bryan comments, boundingRectWithSize:options: is deprecated (not recommended) in OS X 10.11 and later. This is because string styling is now dynamic depending on the context.

For OS X 10.11 and later, see Apple's Calculating Text Height developer documentation.

user_2953960

The answer is to use
- (void)drawWithRect:(NSRect)rect options:(NSStringDrawingOptions)options
but the rect you pass in should have 0.0 in the dimension you want to be unlimited (which, er, makes perfect sense). Example here.

user_933420

You might be interested in Jerry Krinock's great (OS X only) NS(Attributed)String+Geometrics category, which is designed to do all sorts of string measurement, including what you're looking for.

menumachine_501220

Swift 4.2

let attributedString = self.textView.attributedText
let rect = attributedString?.boundingRect(with: CGSize(width: self.textView.frame.width, height: CGFloat.greatestFiniteMagnitude), options: [.usesLineFragmentOrigin, .usesFontLeading], context: nil)
print("attributedString Height = ",rect?.height)
user_56938260

I found helper class to find height and width of attributedText (Tested code)

https://gist.github.com/azimin/aa1a79aefa1cec031152fa63401d2292

Add above file in your project

How to use

let attribString = AZTextFrameAttributes(attributedString: lbl.attributedText!)
let width : CGFloat = attribString.calculatedTextWidth()
print("width is :: >> \(width)")
user_34185560
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