Lecture 1-2 Computer Graphic PDF

Lecture -1- Introduction to Computer Graphics Dr Ahmed Al-Shammari Computer Graphics is an art of drawing pictures on computer screens with the help of programming. It involves computations, creation, and manipulation of data. It is a rendering tool for the generation and m...

Lecture -1- Introduction to Computer Graphics Dr Ahmed Al-Shammari Computer Graphics is an art of drawing pictures on computer screens with the help of programming. It involves computations, creation, and manipulation of data. It is a rendering tool for the generation and manipulation of images. A digital image can be considered a matrix whose row and column. The elements of such a digital array are called image elements, picture elements, pixels. Picture Elements: 1. Pixel: is the smallest addressable screen element. It is the smallest piece of the display screen which we can control. 2. Line : has patron or type. Specification: color, lighting, type, width. Key Components of Computer Graphics 1. Hardware: o Input Devices: Keyboard, mouse, scanner, digital camera, etc. o Output Devices: Monitor, printer, plotter, etc. o Graphics Processing Unit (GPU): Specialized hardware for handling graphics calculations efficiently. 2. Software: o Application Software: Used to create and manipulate graphics. o System Software: Operating system and drivers that manage hardware and software interactions. 3. Algorithms: Mathematical procedures used to perform various graphics tasks (e.g., rendering, shading, animation). Applications of Computer Graphics Gaming: Creating realistic and immersive gaming experiences. Animation: Producing animated movies, TV shows, and commercials. Computer graphics user interfaces (GUIs) – A graphic, mouse oriented paradigm which allows the user to interact with a computer. Design: Designing products, buildings, and environments.  Lecture -1- Introduction to Computer Graphics Dr Ahmed Al-Shammari Visualization: Representing data and information visually. Medical Imaging: Creating 3D models of organs and tissues. Special Effects: Creating visual effects for movies and TV shows. Basic Concepts in Computer Graphics Pixel: The smallest unit of an image, represented by a dot. Resolution: The number of pixels in an image, determining its quality and detail. Color Model: A system for representing colors (e.g., RGB, CMYK). Coordinate System: A framework for specifying the position of points in space. Transformation: A mathematical operation to move, rotate, or scale objects. Rendering: The process of creating an image from a 3D scene. Shading: The process of simulating the effects of light on surfaces. Types of Graphics Raster Graphics: Images composed of individual pixels (e.g., photos, paintings). Vector Graphics: Images composed of mathematical descriptions of lines, curves, and shapes (e.g., logos, drawings). Raster Scan is used by most microcomputer is divided into small rectangles or dots. These dots are referred to as picture elements or pixels. We can consider CRT ( Cathode Ray Tube ) screen to consist of number of vertical and horizontal lines, where each horizontal line is made up of pixels figure ( 1 ). These horizontal lines are called Raster – scan lines, and the video display referred to a raster – scan display. it is similar in the most-general sense to how one's gaze travels when one reads lines of text. Raster Scan provides a refresh rate of 60 to 80 frames per second. Random Scan (Vector Scan) : The electron beam is directed only to the part of the screen where the picture is to be drawn rather than scanning from left to right and top to bottom as in raster scan. It is also called vector display, stroke writing display, or calligraphic display. Picture definition is stored as a set of line-drawing commands in an area of memory referred to as the  Lecture -1- Introduction to Computer Graphics Dr Ahmed Al-Shammari refresh display file. To display a specified picture, the system cycles through the set of commands in the display file, drawing each component line in turn. After drawing all commands are processed, the system cycles back to the first line command in the list. Random-scan displays are designed to draw all the component lines of a picture 30 to 60 times each second. The commands in this technique are Draw a line from A to B Draw a line from B to C Draw a line from C to D Draw a line from D to A Figure 2: Random Scan Graphical User interfaces (GUI): A GUI (graphical user interface) is a system of interactive visual components for computer software. A GUI displays objects that convey information, and represent actions that can be taken by the user. The objects change color, size, or visibility when the user interacts with them. GUI objects include icons, cursors, and buttons. These graphical elements are sometimes enhanced with sounds, or visual effects like transparency and drop shadows. A GUI is considered to be more user-friendly than a text-based command-line interface, such as MS-DOS, or the shell of Unix-like operating systems. The GUI was first developed at Xerox PARC by Alan Kay, Douglas Engelbart, and a group of other researchers in 1981. Later, Apple introduced the Lisa computer with a GUI on 1983. Computer graphic references: 1. M.Berger,” Computer Graphic with Pascal “, B/C Publishing Company, 1984. 2. J.D.Foley & A.Dametal,” Introduction to Computer Graphic “, Addison –wesly, 1993. 3. D.Hearn & M.p.Baker,” Computer Graphics “, 2nd Ed., Prentice – Hall, 1994. 4. David J. Eck, ” Introduction to Computer Graphics“: A Practical Learning Approach (Chapman & Hall/CRC Computer Graphics, Geometric Modeling, and Animation.) Version 1.1, 2016