Raster Graphics

1
Raster Graphics

• Raster formats used for storing digitized
  photographs, scanned artwork.
• comprised of individual pixels
• As a rule, higher resolutions deliver greater
  accuracy
• Large files take longer to transmit, print and
  process
• Common formats include TIFF, JPEG, GIF, PCX,
  BMP. Adobe Photoshop, Picture Publisher, and
  Fractal Painter are among the most popular
  packages for creating raster graphics.

2
Vector Graphics

• Vector graphics are assembled using geometric
  primitives such as polygons, polylines, curves,
  circles, rectangles, etc. Unlike raster graphics,
  where resolution is pre-determined, vector
  graphics are resolution independent. In other
  words, image quality is directly related to the
  capability of your printer or output device.

3
Vector Graphics

• An advantage of this approach is that you can
  resize graphics without any fear of image
  degradation. A raster file can sometimes appear
  "coarse" or "jagged", depending on how the image
  is displayed. Vector graphics on the other hand
  look great under all conditions!
• Also known as objects

4
Vector Graphics
When blown up, the raster file reveals what are
commonly known as the "Jaggies"
5
3D Modelling

• Using computer graphics to represent all three
  dimensions
• Models can be rotated, stretched, viewed from
  many angles
• Used for walk-throughs or simulations
• Used for movie and TV special effects

6
CAD / CAM

• 3D Modelling used for Computer-Aided Design and
  Computer-Aided Manufacture
• Physical properties can be simulated
• Weight, volume, centre of gravity
• Products can be manufactured on screen
• Production machines can be controlled by
  networked computers

7
Presentation Graphics

• Using computer graphics as visual aids
• Training, lectures, sales presentations
• Animated images
• Incorporated in multimedia presentations
• Easy to integrate various documents from other
  packages

8
Dynamic Media

• Can use computers to paint and draw
• Why not animate?
• Easier and quicker to produce sequences from
  still pictures than by hand
• Flash presentations

9
Digital Video

• Editing video tapes
• Splicing scenes, add transitions, create titles
• Video must be in digital form to edit
• Video digitiser converts analogue waves to
  digital data
• Modern digitisers use USB port for fast data
  transfer

10
Data Compression

• Digital video makes big demands on hardware
• Short video clips can occupy one CD-ROM
• Lossy data compression used to reduce storage
  requirement
• Loss of image quality

11
Hypertext

• Word processors give WYSIWYG
• Not always necessary if document not to be
  presented
• Dynamic, cross-referenced document
• Uses links
• Allows non-sequential navigation
• World Wide Web

12
Hypertext

• Can be disorienting
• Dont always have the links you want
• Cant scribble notes in the margin
• Many find screens harder to read than books

13
Multimedia

• Combination of text, graphics, animation, video,
  voice and sound effects to communicate
• Just like the evening news on TV!
• Computers allow interactive multimedia
• Will respond to users actions
• User can actively participate
• Good for training