3. Graphics Devices -INPUT.   

A problem with graphics is that it is not easy for a user to interact with the environment of the graphics area.

We require an input device to capture data - either commands or values or simply selection data - so that the user may interact with the program.

       Input Types  
       Keyboard Devices.  
       Cross Hair Feedback.  
       Analogue devices.  
       Digital devices.  
       Mouse and Trackball.  
       Light Pens.  
       Joysticks.  
       Digitisers.  
       2D and 3D Scanners.  
       Camera/Video input.  
       Character Recognition.  

These are the dominant types of input devices.