CGContextAddRectcontext

CGContextAddRect is a function in the Core Graphics framework of Apple's iOS and macOS operating systems, used for drawing operations within the Quartz 2D graphics system. It is part of the broader set of functions designed to manipulate a graphics context, which serves as a destination for drawing commands. The function allows developers to add a rectangular path to the current path of the graphics context, effectively defining a shape that can later be filled, stroked, or clipped.

The function signature for CGContextAddRect is as follows: void CGContextAddRect(CGContextRef context, const CGRect rect). Here, *context* is a reference to the current graphics context, and *rect* is a CGRect structure representing the rectangle to be added. The rectangle is defined by its origin point (lower-left corner) and its size (width and height). When called, the rectangle is added to the current path of the context, meaning it will be included in subsequent drawing operations unless the path is modified or cleared.

CGContextAddRect is commonly used in conjunction with other Core Graphics functions such as CGContextFillPath, CGContextStrokePath, or CGContextClip, which apply specific visual effects to the defined path. For example, calling CGContextAddRect followed by CGContextFillPath will fill the rectangle with the current fill color and pattern. Similarly, combining it with CGContextStrokePath will draw the outline of the rectangle using the current stroke properties.

This function is particularly useful in scenarios where dynamic or programmatically generated shapes are required, such as custom UI elements, animations, or graphical user interfaces. It provides a straightforward way to define geometric shapes without relying on rasterized images, enabling smoother scaling and better performance in certain cases. Developers often use it alongside other Core Graphics functions to create complex compositions of shapes, gradients, and textures.