System.Drawing namespace in .NET Framework Class Library
The System.Drawing namespace provides access to GDI+ basic graphics functionality. GDI+ is a subsystem of Windows that allows drawing to the screen or to printers, and provides developers with advanced functionality for rendering user interfaces and data.
For example, System.Drawing can be used to generate graphics dynamically, from a web application, before downloading those graphics to a platform-independent browser.
The Graphics class provides methods for drawing to the display device. Classes such as Rectangle and Point encapsulate GDI+ primitives. The Pen class is used to draw lines and curves, while classes derived from the abstract class Brush are used to fill the interiors of shapes.