Learning Cocoa

NSBezierPath

An NSBezierPath object allows you to create paths using PostScript-style commands. Paths consist of straight and curved line segments joined together. Paths can form recognizable shapes such as rectangles, ovals, arcs, and glyphs; they can also form complex polygons using either straight or curved line segments. A single path can be closed by connecting its two endpoints, or it can be left open.

An NSBezierPath object can contain multiple disconnected paths, whether they are closed or open. Each of these paths is referred to as a “subpath” of the NSBezierPath object. The subpaths of an NSBezierPath object must be manipulated as a group. The only way to manipulate subpaths individually is to create separate NSBezierPath objects for each.

For a given NSBezierPath object, you can stroke the path’s outline or fill the region occupied by the path. You can also use the path as a clipping region for views or other regions. Using methods of NSBezierPath, you can also perform hit detection on the filled or stroked path. Hit detection is needed to implement interactive graphics, as in rubber banding and dragging operations.

Construct Paths

You can create an instance of NSBezierPath using either of the class methods bezierPath or bezierPathWithRect:. The bezierPath method initializes a new Bezier-path object with an empty path while the bezierPathWithRect: method creates a path with the specified rectangle. (You can also allocate memory for a new instance of NSBezierPath and ...