Custom drawing selection in NSTextView

Question

I've got a NSTextView where I'd like to control drawing of the highlight/selection. Anyone know which method I have to overwrite so I can control what to draw in the selection rect?

Answer 1

You do not specify what you want to draw, so it's not easy to give you a straight answer.

If it's just an attributed string (Font, Style, Color, Background), you do not need anything fancy, just look for NSAttributedString. There are methods like -setSelectedTextAttributes: and the delegate method -textViewDidChangeSelection:

Generally, you should not subclass NSTextView if you don't have a very good reason to do so. You can do almost anything by just utilizing the usual delegation mechanisms.

If it's something very customized, there is a variety of possibilities depending on if you want to customize the selection (-setSelectedRange:) draw an overlay view (get the frame of the selectedRange) or mess around with the low level layout engine (-layoutManager). It really depends.

Answer 2

If you don't want to use the standard attributes to highlight text, eg by using an CALayer, you can get the rects containing the selection from the layoutManager of the NSTextView.