The Input Devices are the hardware that is used to transfer transfers input to the computer. The data can be in the form of text, graphics, sound, and text. Output device display data from the memory of the computer. Output can be text, numeric data, line, polygon, and other objects.

Input Devices in Computer Graphics:

  1. Keyboard
  2. Mouse
  3. Trackball
  4. Spaceball
  5. Joystick
  6. Light Pen
  7. Digitizer
  8. Touch Panels
  9. Voice Recognition
  10. Image Scanner

1. Keyboard:

The most commonly used input device is a keyboard. The data is entered by pressing the set of keys. All keys are labelled. A keyboard with 101 keys is called a QWERTY keyboard. The keyboard has alphabetic as well as numeric keys. Some special keys are also available.

  1. Numeric Keys: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  2. Alphabetic keys: a to z (lower case), A to Z (upper case)
  3. Special Control keys: Ctrl, Shift, Alt
  4. Special Symbol Keys: ; , " ? @ ~ ? :
  5. Cursor Control Keys: ↑ → ← ↓
  6. Function Keys: F1 F2 F3...
  7. Numeric Keyboard: It is on the right-hand side of the keyboard and used for fast entry of numeric

Function of Keyboard:

  1. Alphanumeric Keyboards are used in (Computer Aided Drafting)
  2. Keyboards are available with special features line screen co-ordinates entry, Menu selection or graphics functions,
  3. Special purpose keyboards are available having buttons, dials, and switches. Dials are used to enter scalar Dials also enter real numbers. Buttons and switches are used to enter predefined function values.

2. Mouse:

A Mouse is a pointing device and used to position the pointer on the screen. It is a small palm size box. There are two or three depression switches on the top. The movement of the mouse along the x-axis helps in the horizontal movement of the cursor and the movement along the y-axis helps in the vertical movement of the cursor on the screen. The mouse cannot be used to enter text. Therefore, they are used in conjunction with a keyboard.

3. Trackball

It is a pointing device. It is similar to a mouse. This is mainly used in notebook or laptop computer, instead of a mouse. This is a ball which is half inserted, and by changing fingers on the ball, the pointer can be moved.

4. Space ball:

It is similar to trackball, but it can move in six directions where trackball can move in two directions only. The movement is recorded by the strain gauge. Strain gauge is applied with pressure. It can be pushed and pulled in various directions. The ball has a diameter around 7.5 cm. The ball is mounted in the base using rollers. One-third of the ball is an inside box, the rest is outside.


  1. It is used for three-dimensional positioning of the
  2. It is used to select various functions in the field of virtual
  3. It is applicable in CAD applications.
  4. Animation is also done using space ball.
  5. It is used in the area of simulation and

5. Joystick:

A Joystick is also a pointing device which is used to change cursor position on a monitor screen. Joystick is a stick having a spherical ball as it’s both lower and upper ends as shown in fig.

The lower spherical ball moves in a socket. The joystick can be changed in all four directions. The function of a joystick is similar to that of the mouse. It is mainly used in Computer Aided Designing (CAD) and playing computer games.

6. Light Pen:

Light Pen (similar to the pen) is a pointing device which is used to select adisplayed menu item or draw pictures on the monitor screen. It consists of a photocell and an optical system placed in a small tube. When its tip is moved over the monitor screen, and pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signals to the CPU.


  1. Light Pens can be used as input coordinate positions by providing necessary
  2. If background color or intensity, a light pen can be used as a
  3. It is used as a standard pick device with many graphics
  4. It can be used as stroke input
  5. It can be used as valuators

7. Digitizers: 

The digitizer is an operator input device, which contains a large, smooth board (the appearance is similar to the mechanical drawing board) & an electronic tracking device, which can be changed over the surface to follow existing lines. The electronic tracking device contains a switch for the user to record the desire x & y coordinate positions. The coordinates can be entered into the computer memory or stored or an off-line storage medium such as magnetic tape.

8. Touch Panels:

  • Touch Panels is a type of display screen that has a touch-sensitive transparent panel covering the screen. A touch screen registers input when a finger or other object comes in contact with the
  • When the wave signals are interrupted by some contact with the screen, that located is
  • Touch screens have long been used in military

9. Voice Systems (Voice Recognition):

  • Voice Recognition is one of the newest, most complex input techniques used to interact with the computer. The user inputs data by speaking into a microphone. The simplest form of voice recognition is a one-word command spoken by one Each command is isolated with pauses between the words.
  • Voice Recognition is used in some graphics workstations as input devices to accept voice commands. The voice-system input can be used to initiate graphics operations or to enter data. These systems operate by matching an input against a predefined dictionary of words and phrases.

10. Image Scanner

  • It is an input device. The data or text is written on paper. The paper is fed to scanner. The paper written information is converted into electronic format; this format is stored in the computer. The input documents can contain text, handwritten material, picture
  • By storing the document in a computer document became safe for longer period of The document will be permanently stored for the future. We can change the document when we need. The document can be printed when needed.
  • Scanning can be of the black and white or colored picture. On stored picture 2D or 3D rotations, scaling and other operations can be applied.

Output Devices in Computer Graphics:

  1. Printers
  2. Plotters

1. Printers:

A printer is a peripheral device which is used to represent the graphics or text on paper. The quality is measured by its resolution. The resolution of any printer is measured in dot per inch (dpi).

The printer usually works with the computer and connected via a cable. In present, many digital device support printer features so that we can use Bluetooth, Wi-fi, and cloud technology to print.

Some types of printers are:

  1. Impact Printers
  2. Non-impact Printers

A. Impact Printers

In impact printers, there is a physical contact established between the print head, ribbon, ink-cartridge, and paper.

The printers hit print head on an ink-filled ribbon than the letter prints on the paper. Impact printers are works like a typewriter.

These printers have three types:

  1. Daisy Wheel Printers
  2. Drum Printers
  3. Dot Matrix Printer

Types of Printers:

a. Daisy Wheel Printers:

By these, we can print only one character at a time. The head of this printer looks like a daisy flower, with the printing arms that appear like petals of a flower; that’s why it is called “Daisy printer.” It can print approx. 90 characters per second.

Daisy Wheel Printer

Daisy Wheel Printer

Daisy wheel printers are used to print the professional quality document. It is also called “Letter Quality Printer.”


  1. More reliable
  2. Better printing Quality


  1. Slow than Dot Matrix
  2. More Expensive
  3. Noisy in operation

b. Drum Printers:

It has a shape like a drum, so it is called “Drum Printer.” This type of printer contains many characters that are printed on the drum. The surface of the drum is break down into the number of tracks. Total tracks are equal to character132. A drum will have 132 tracks. The number of tracks is divided according to the width of the paper. It can print approx. 150-2500 lines per minute.


  1. High Speed
  2. Low Cost


  1. Poor Printing Quality
  2. Noisy in Operation

b. Dot Matrix Printer:

It is also known as the “Impact Matrix Printer.” Dot Matrix Printer can print only one character at a time. The dot matrix printer uses print heads consisting of 9to 24 pins. These pins are used to produce a pattern of dots on the paper to create a separate character. Dot-matrix printer can print any shapes of character, special character, graphs, and charts.


  1. Low Printing Cost
  2. Large print size
  3. Long Life


  1. Slow speed
  2. Low Resolution

B. Non-impact Printers

In Non-impact printers, there is no physical contact between the print head or paper head. A non-impact printer prints a complete page at a time. The Non-impact printers spray ink on the paper through nozzles to form the letters and patterns. The printers that print the letters without the ribbon and on papers are called Non-impact printer. Non-impact printers are also known as “Page Printer.”

These printers have two types:

  1. Inkjet Printer
  2. Laser Printer

a. Inkjet Printer:

It is also called “Deskjet Printer.” It is a Non-impact printer in which the letters and graphics are printed by spraying a drop of ink on the paper with nozzle head.

A Color inkjet printer has four ink nozzles, sapphire, red, yellow, and black, so it is also called CMYK printer. We can produce any color by using these four colors. The prints and graphics of this printer are very clear. These printers are generally used for home purposes.


  1. High-Quality Printout
  2. Low noise
  3. High Resolution


  1. Less Durability of the print head
  2. Not suitable for high volume printing
  3. Cartridges replacement is expensive

b.  Laser Printer:

It is also called “Page Printer” because a laser printer process and store the whole page before printing it. The laser printer is used to produce high-quality images and text. Mostly it is used with personal computers. The laser printers are mostly preferred to print a large amount of content on paper.


  1. High Resolution
  2. High printing Speed
  3. Low printing Cost


  1. Costly than an inkjet printer
  2. Larger and heavier than an inkjet printer

2. Plotters

A plotter is a special type of output device. It is used to print large graphs, large designs on a large paper. For Example: Construction maps, engineering drawings, architectural plans, and business charts, etc. It was invented by “Remington rand” in 1953.It is similar to a printer, but it is used to print vector graphics.

Types of Plotter:

  1. Flatbed Plotter
  2. Drum Plotter

a. Flatbed Plotter:

In a flatbed plotter, the paper is kept in a stationary position on a table or a tray. A flatbed plotter has more than one pen and a holder. The pen rotates on the paper upside-down and right-left by the using of a motor. Every pen has a different color ink, which is used to draw the multicolor design. We can quickly draw the following designs by using a flatbed printer.

For Example: Cars, Ships, Airplanes, Dress design, road and highway blueprints, etc.

Advantages of Flatbed Plotter

  1. Larger size paper can be used
  2. Drawing Quality is similar to an expert

Disadvantages of Flatbed Plotter

  1. Slower than printers
  2. More Expensive than printers
  3. Do not produce high-Quality text printouts

b. Drum Plotter:

It is also called “Roller plotter.” There is a drum in this plotter. We can apply the paper on the drum. When the plotter works, these drums moves back and forth, and the image is drawn. Drum plotter has more than one pen and penholders. The pens easily moves right to left and left to right. The movement of pens and drums are controlled by graph plotting program. It is used in industry to produce large drawings (up to A0).

Advantages of Drum Plotter:

  1. Draw Larger Size image
  2. We can print unlimited length of the image

Disadvantages of Drum Plotter:

  1. Very costly