Computer Graphics Lecture 1 Introduction to Computer Graphics

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1 Computer Graphics Lecture 1 Introduction to Computer Graphics
Graphics Hardware Applications of Graphics

2 What is Computer Graphics?
Computer Graphics- is a field of computer science which is used in almost every application of computer software. Graphics = images or pictures (not text) Graphics Systems = Images + Text + Sound Computer Graphics involves display, manipulation and storage of pictures using a computer. Pictures can be: 1. Photographs 2. Movies 3. Drawings (for example, building architectures, etc)

3 Components of a Graphics System
A graphics system consists of a computer that supports: Fast processor Large memory Display device (Color monitor) Input devices Output devices (Printers) Frame Buffer

4 Input devices 1. Keyboards : An alphanumeric keyboard on a graphics system is used for entering text strings. The keyboard is an efficient device for inputting nongraphic data. 2. Mouse : A mouse is small box used to position the screen cursor. 3. Trackball : A trackball is a ball that can be rotated with the fingers or palm of the hand to produce screen-cursor movement. 4. Joystick : A joystick consists of a small, vertical stick mounted on a base that is used to steer the screen cursor around.

5 5. Image Scanners : Drawings, graphs, color and black-and-white photos, or text can be stored for computer processing with an image scanner by passing an optical scanning mechanism over the information to be stored. 6. Touch Panels : allow displayed objects or screen positions to be selected with the touch of a finger. 7. Voice Systems : Speech recognizers are used in some graphics systems as input devices to accept voice commands The voice-system input can be used to initiate graphics operations or to enter data.

6 Framebuffer Framebuffer - A block of contiguous memory that stores the contents of an image (to be displaced) pixel by pixel. Pixel - one element of the framebuffer

7 Frame Buffer

8 Applications of Computer Graphics
Computer graphics is used in almost all areas of computer science. Graphical User Interface (GUI): the interface between users and the application program. It has many components for example, menus, icons, buttons, etc. Office Automation: Standard packages of MS Word, Excel, Powerpoint use GUI. Entertainment: Computer Graphic systems are used to design movies, video games, animation movies, cartoons etc. Education: GUI helps us in preparing presentations, video lectures, etc.

9 5. Computer Aided Design (CAD): one of the most important application of graphics is in engineering and architectural systems. CAD – use of computers to help in creation, modification and analysis of a design. Design can be of buildings, automobiles, aircraft, computers etc. There are many software packages for CAD for example, AutoCAD, DRAFT IT, etc.

10 Object to be designed is displayed in a wireframe outline called blueprint or skeleton.
It shows the shape and features of the object to be designed

11 6. Computer Art: another application of graphics Computer Art
Fine Art Commercial Art Paint programs -Movies Pixel Paint, SuperPaint - Ad’s Animation software

12 7. Image Processing: Changing or modifying existing pictures to improve picture quality. It includes: - rearranging picture parts - enhancing color separations - improve quality of shading

13

14 Types of Computer Graphics
Two Types of Computer Graphics: Interactive Graphics Non-Interactive/ Passive Graphics Interactive Computer Graphics It involves two way communication between computer and user. User is given control over the image by providing an input device that takes the user request to the computer. Example: Flight simulator used to train pilots. Advantages: Fuel saving, safety. Another example is video game controller.

15 2. Non-Interactive Graphics / Passive Graphics
In this type of computer graphics, user has no control over the images. Images are displayed with the help of a static stored program and according to the instructions that are written in the program. Example: screensavers.