Basic of computer graphic - Computer Graphic - Notes

Basic of computer graphic - Computer Graphic - Notes

• 1.
  Definition of ComputerGraphics Computer Graphics is a sub-fields of computer science and is concerned with digitally synthesizing and manipulating visual content. Computer Graphics is the study of techniques to improve communication between human and machine. The word computer graphics means picture , graph or sense is dream with the help of computer. OR
• 2.
  Application of ComputerGraphics • Engineering / Scientific Software, Business Software. • T.V. channels, space simulation training. • PCB designing, map preparation. • User Interface, Animation. • Making Charts, Image Processing. • Office Automation. • Desktop Publishing. • CAD / CAM. • Art and Commerce. • Process Controlling. • 'Visual Effects' in Movies and Computer Games.
• 3.
  Pixel and FrameBuffer, Resolution. The pixel is the smallest addressable screen element. It is the smallest piece of the display screen which we can contact. Each pixel has name on address. Computer Graphic images are made by setting the intensity and color of the pixels which compose the scree. The intensity value for all pixels are placed into an array in our computer memory. This array, which contacts an internal representation of the image is called the frame buffer. It collects and stores pixel values for use by the display choice. Resolution useless to the numbers of dots on the screen. It is expressed as a pain of numbers that give the number of dots on a horizontal line and the number of such vertical line. ex. 640 X 480, 800 X 600 etc.
• 4.
  Stages for graphicspipeline. 1. Modeling transformation. 2. Per-vertex lighting. 3. Viewing transformation. 4. Primitive generation. 5. Projection transformation. 6. Clipping. 7. Scan conversion or rasterization. 8. Texturing, fragment shading. 9. Display. 10. The graphics pipeline in hardware.
• 5.
  Bitmap Graphics VSVector Graphic (Com) SR Bitmap Graphics Vector based Graphics 1 Pixels are used to form Bitmap images. Mathematical formulas are used to form vector based images. 2 Larger in size than vector based. Smaller in size than bitmap based. 3 Bitmap graphics are affected by resolution. Does not affect by resolution. 4 Modification in bitmap graphics is more difficult. Modification in vector graphics is easy. 5 Conversion of Bitmap graphics to Vector graphics is more difficult. Vector graphics can be converted in to Bitmap graphics easily. 6 More suitable for complex images. Not appropriate for complex images. 7 e.g. GIF, JPEG, BMP, etc. e.g. Postscripts and True Type fonts.
• 6.
  Text Mode &Graphics Mode Text Mode 80 columns 25rows Graphics Mode 640 480
• 7.
  Graphics Mode functions 1.Initgraph 2. Path ("C:/tc/bgi") 3. Line() 4. Closegraph() 5. Restorcrtmode()
• 8.
  Raster Scan display Userprogram Frame buffer Raster display
• 9.
  Random Scan display
• 10.
  Random ScanVS RasterScan (Com) SR Random Scan Raster Scan 1 Random scan operate by directing the electron beam to only those parts of the screen where the picture is to be drawn. The electron beam starts at top left corner of the screen and moves horizontally to the right. 2 Creation of diagram using random scan becomes easier, so can be used in engineering and scientific drawings. Raster graphics can be used in animation. 3 Pen plotters and direct storage view tubes (DVST) devices are used. Cathode ray tubes (CRT) are used. 4 The cost of devices used for random scan is much higher. The cost of devices used for raster scan is much cheaper. 5 Requires less memory. Requires more memory. 6 Requires intelligent electron beam. i.e. processor controlled. No such requirement.
• 11.
  Electron gun ofCRT
• 12.
  A B C B A Fig 1.5.1 Fig1.5.3Fig 1.5.2 Current position X, Y A B C D E Current position DX DY X, Y Fig 1.5.4 A B C D A B C D Fig 1.5.5 Fig 1.5.6 Primitive Operation
• 13.
  Latest trends inComputer graphics A. Virtual reality (VR) Virtual reality means Computer generated environment to interact with and be immersed in. It immerses users in a computer graphical digital environment. It can also be defined as a creation of simulated environment by using computer technology. we can look in every direction as if we are physically at that location. B. Augmented Reality (AR) In this technology users interact with the real world while digital controls are address to it. is the result of applying technology to superimpose information such as sounds, images and text are the real world which we see.