自动调整NSTextView的大小及其字体大小

Question

I'm trying to make my NSWindow autoresizable. I've gotten most of my UI items to resize, but one of the few remaining objects that pose issues are NSTextViews: indeed, I can't find a way to calculate the new font size once the NSTextView has been resized.

For NSTextFields, I had found a method that would find the font size based on the length of the text. Apparently, there doesn't seem to be an equivalent method for multi-line text containers (unless I just haven't found it).

The only actual place I found that mentionned something of the sort is here: http://boutcher.tumblr.com/post/7842216960/nstextview-auto-resizing-text

However, I wasn't able to implement this code into my application, as there seems to be an error I can't fix with the way an NSLayoutManager is created.

Has anyone done this in the past? I'm considering just allowing the user to resize to just one size, so I can hardcode the font size... It's a real pain dealing with these NSTextViews !

Answer 1

See the sizeWithAttributes: method in “NSString Application Kit Additions Reference.”

It returns an NSSize, which you can compare to the textview's current frame.size.

For the “Attributes” arg make an NSDictionary with an NSFont as the object and NSFontAttributeName as the key. (Don't be confused by that constant. It looks like it's a key for a string, but it is not; it is a key for the font itself.)

Get the string from the textview: [[yourTextView textStorage] string] . Get the familyName of the font you are using and its current point size, a CGFloat. Compose fonts to test using the constructor [NSFont fontWithName:familyName size:floatChanged] .

Once you've arrived at the correctly sized font, use it to make a new NSAttributedString out of the old string. Just use the "attributes" dictionary you made above (the one that produced the correct size) and feed it to NSAttributedString's initWithString:attributes constructor.

Assign that attributed string to the textStorage (itself a subclass of NSMutableAttributedString): [[yourTextView textStorage] setAttributedString:thatYouJustMade] .

Note: If the textview employs attributes like underlining or fore/background coloring, or italicized/bold fonts, you must get that information from the textStorage and incorporate it into the new attributed string. It's doable. Look at the class refs for NSAttributedString and NSMutableAttributedString.