NSTextView is the front-end class to MacOS's Application Kit text system. It draws the text managed by the back-end components and handles user events to select and modify its text. While NSTextView is a subclass of NSText—which declares the most general Cocoa interface to the text system—NSTextView adds major features beyond the capabilities of NSText.
Text views are user interface objects instantiated from the NSTextView class. Text views typically display multiple lines of text laid out in paragraphs with all the characteristics of sophisticated typesetting. A text view is the main user interface to the Cocoa text-editing system. It handles user events to provide text entry and modification, and to display any font, including those of non-English languages, with arbitrary colors, styles, and other attributes.
The Cocoa text system supports text views with many other underlying objects providing text storage, layout, font and attribute manipulation, spell checking, undo and redo, copy and paste, drag and drop, saving of text to files, and other features. NSTextView is a subclass of NSText, which is a separate class for historical reasons. You don’t instantiate NSText, although it declares many of the methods you use with NSTextView. When you put an NSTextView object in an NSWindow object, you have a full-featured text editor whose capabilities are provided “for free” by the Cocoa text system.
