Comprehensive Introduction to Computer Graphics and Raster Scan Technologies

Comprehensive Introduction to Computer Graphics and Raster Scan Technologies

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  Unit–I: Fundamentals ofComputer Graphics and Raster Scan Graphics Computer Graphics
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  1.1 Basics ofComputer Graphics Definition Computer Graphics is the branch of computer science that deals with creating, storing, manipulating, and displaying pictures, images, and visual information using computers.
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  • Example Applications •Computer-Aided Design (CAD) • Video Games • Animation and Movies • Medical Imaging • Virtual Reality (VR) • Scientific Visualization • Education and Training • Image Processing • Graphical User Interfaces (GUI)
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  Scope of ComputerGraphics • Computer graphics is widely used in: 1. Engineering Design • Building plans • Machine parts design • Circuit design
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  2. Entertainment • Movies •Animation • Gaming 3. Education • Interactive learning • Simulations 4. Medical Field • MRI visualization • CT scan analysis
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  Graphics Standards • Graphicsstandards ensure that graphical data is displayed consistently across different systems. • Common Graphics Standards 1. GKS (Graphics Kernel System) • First international graphics standard. • Device-independent.
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  2. PHIGS (Programmer'sHierarchical Interactive Graphics System) • Supports 3D graphics. • Interactive graphics applications. 3. OpenGL • OpenGL • Open-source graphics library. • Used for 2D and 3D graphics. 4. DirectX • Microsoft DirectX • Developed by Microsoft. • Mainly used for gaming applications.
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  • Shapes inComputer Graphics (Basic graphical objects): • Point • A single pixel location. Example:(10,20) • Line • Connects two points. • Circle • All points at equal distance from center. • Rectangle • Four-sided polygon. • Polygon • Closed figure with multiple sides. • Examples: Triangle ,Pentagon ,Hexagon
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  Colors in ComputerGraphics • Color is represented through intensity values. • RGB Model • Most common color model. • R = Red • G = Green • B = Blue
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  Example: Color RGB Value Red(255,0,0) Green (0,255,0) Blue (0,0,255) White (255,255,255) Black (0,0,0)
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  Color Interaction • Colorinteraction refers to how colors affect each other when displayed together. • Example: Black text on white background. Harmony Pleasant combination of colors. • Example: Blue and Green. Brightness Effect Nearby colors can appear lighter or darker.
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  Graphical User Interface(GUI) • A GUI allows users to interact using graphical elements. Features of GUI • Windows • Display application content. • Icons • Represent files or programs. • Menus • List commands. • Buttons
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  • Advantages • Easyto use • User friendly • Less typing required • Faster interaction
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  1.2 Raster Scanand Random Scan Display Devices Raster Scan Display Definition • Raster scan display uses a matrix of pixels. • The screen is scanned line by line from top to bottom. Working • Electron beam starts from top-left. • Moves horizontally. • Completes one line. • Moves to next line. • Repeats until bottom.
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  Characteristics • Pixel based •Suitable for images • Used in modern monitors Advantages • Realistic images • Supports shading • Supports color graphics Disadvantages • Requires more memory • Lower line quality
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  Example • LCD Monitor •LED Monitor
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  Random Scan Display(Vector Display) Definition • Random scan displays draw only required lines. • Beam moves directly between points. Working • Beam moves to starting point. • Draws required line. • Moves to next line. Characteristics • Line based • Better line quality • Less memory required
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  Advantages • High resolutionlines • Smooth graphics Disadvantages • Cannot display realistic images • Not suitable for complex scenes
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  Raster Scan vsRandom Scan Feature Raster Scan Random Scan Method Pixel Based Line Based Memory High Low Image Quality Good for Pictures Good for Lines Cost Low High Speed Faster Slower Used In Modern Monitors Vector Displays
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  1.3 Line DrawingAlgorithms • Line drawing algorithms determine pixels required to display a line. • Digital Differential Analyzer (DDA) Algorithm
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  • Principle • Aline is generated using incremental calculations. • Given: • (x1,y1) (x2,y2) • Calculate: • (increments) • DDA Formula( digital differential analyzer)
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  DDA Algorithm Steps •Read starting point. • Read ending point. • Calculate dx and dy. • Find steps. • Calculate increments. • Plot first point. • Generate remaining points.
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  Example • Draw linefrom: • (2,2) to (8,5) • Step 1 • dx = 8-2 = 6 dy = 5-2 = 3 • Step 2 • steps = max(6,3)=6 • Step 3 • xinc = 6/6 = 1 yinc = 3/6 = 0.5
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  • Advantages • Easyimplementation • Simple calculations • Disadvantages • Uses floating-point operations • Less efficient
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  What is aLine Drawing Algorithm? • A Line Drawing Algorithm is a method used to determine which pixels should be turned ON to display a straight line on a computer screen. • Since a computer screen is made up of tiny square pixels, it cannot draw a perfectly continuous line. Instead, it lights up the nearest pixels to form a line. • There are two famous line drawing algorithms: • Digital Differential Analyzer (DDA)
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  What is DDAAlgorithm? • Definition: • The Digital Differential Analyzer (DDA) is an incremental scan conversion algorithm that calculates intermediate points between two endpoints using floating-point arithmetic. • It works by increasing one coordinate step by step and calculating the corresponding coordinate using the slope of the line.