GDI stands for ( Graphic Device Interface ) and it is a way to work with paining graphic objects such as painting on windows, forms or other media. We can write GUI application with help of some kind of visual interface in the form of windows and controls. There is only one way to see the visual interface through hardware, such as printer and monitor. GDI is a set of C++ classes that class libraries provides functionality to render data to a program to hardware devices with the help of device drivers and working with in program and the hardware for transferring information one place to another place.