CGPathRef

CGPathRef is an opaque type in the Core Graphics framework of Apple's operating systems that represents a mutable or immutable path. Paths are essentially collections of connected lines and curves, forming outlines of shapes. CGPathRef is a fundamental building block for drawing and manipulating vector graphics. It can be used to define the boundaries of shapes for filling, stroking, clipping, or as a basis for animations.

Paths are constructed by adding segments, such as lines, curves (quadratic and cubic Bézier), and arcs. A path can be started, closed, and have subpaths created within it. Operations like moving to a point, adding a line to another point, or adding a curve from one point to another are common methods for defining a path's geometry.

CGPathRef objects are often used in conjunction with other Core Graphics drawing functions. For instance, a CGPathRef can be passed to `CGContextFillPath` to fill the area enclosed by the path, or to `CGContextStrokePath` to draw the outline of the path. It plays a crucial role in rendering complex shapes and defining regions for interaction in graphical user interfaces. The immutability of a CGPathRef once created ensures that its shape remains consistent until explicitly modified or a new path is generated.