NSTextView and NSString differences in text rendering
If you're drawing a string in Cocoa, you may notice discrepancies between how the text is rendered in a NSTextView and how it's rendered when using the NSString (or NSAttributedString) AppKit drawing methods. This is because of they each use a different default NSTypesetterBehavior, which results in slightly different line spacings. When you draw a string using the drawing convenience methods - like
[string drawAtPoint:point] - it uses
NSTypesetterBehavior_10_2_WithCompatibility1. If you then place the same NSString (or NSAttributedString) into a NSTextView, it will look different because NSTextView uses
NSTypesetterLatestBehavior. This isn't a huge problem unless you're rendering them right next to/on top of each other. For example, drawing a string into a NSCell in a NSTableView, then dynamically overlaying a NSTextView for selecting/editing. In that case, the text will jump around and it will look horrible.
Fortunately, after much searching, I found there is an easy solution. You need to change the typesetter behavior of the NSTextView's underlying NSLayoutManager, since I don't believe there is a way to the change the typesetter behavior of the string drawing methods.
That's it and your text will render exactly the same. You should also do this if you're programmatically calculating the height of a text block before drawing, or you'll get one height for the calculation, but when you draw the text, it won't fit.
1Apple's docs that mention this: http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/TextLayout/Tasks/DrawingStrings.html#//apple_ref/doc/uid/20001808-SW1