Chapter 1 Notes
⇑ ⇑ Home
Applications of Computer Graphics
Computer graphics user interfaces - GUIs.
A graphic, mouse-oriented paradigm which allows the user to interact with a computer.
Business presentation graphics - "A picture is worth a thousand words".
Cartography - drawing maps
Weather Maps - real time mapping, symbolic representations
Satellite Imaging - geodesic images
Photo Enhancement - sharpening blurred photos
Medical imaging - MRIs, CAT scans, etc. - non-invasive internal examination.
Engineering drawings - mechanical, electrical, civil, etc. - replacing the blueprints of the past.
Typography - the use of character images in publishing - replacing the hard type of the past.
Architecture - construction plans, exterior sketches - replacing the blueprints and hand drawings of the past.
Art - computers provide a new medium for artists.
Motivations for Graphics Use
Training - flight simulators, computer aided instruction, etc.
Entertainment - movies and games.
Simulation and modeling - replacing physical modeling and enactments.
Communications - in general.
Computer Hardware for Graphics
Keyboard - good for text, awkward for graphics.
Mouse - popular and convenient for graphics.
Data tablet - good for accurate digitalization of existing hard copies as vector sets.
Scanner - - good for digitalization of existing hard copies as pixel sets.
Light pen - usually not as convenient as a mouse.
Touch screen - more useful for menu selection than for graphics.
Joystick - useful for interactive graphics (games).
CRT - the common display device for personal computers.
LCD - A smaller, lighter, lower powor replacement for the CRT.
LED - A smaller, lighter, lower powor replacement for the CRT.
Plasma screens - a more expensive but brighter alternative to LCDs.
Printers - today's printers are good for both text and graphics.
Plotters - good for vector graphics.
Oscilloscope - an early vector graphics output device.
Vector Graphics and Raster Graphics
Generation of images from mathematical descriptions that determine the position, length, and direction in which lines are drawn.
Vector graphics is also called stroke or line drawing.
Oscilloscopes and some plotters are vector graphics devices.
Generation of images as a collection of small, independently controlled dots (pixels) arranged in rows and columns.
Raster graphics is also referred to as pixel graphics.
Almost all current computer output devices, including CRTs, LCDs, LEDs, and plasma screens, use raster graphics.
Raster graphics cannot draw perfect curved or slopping lines.
The appearance of curved or sloping lines improves as the size of the pixels decreases.
Software techniques can also be used to improve the visual appearance of pixel based lines.
Computer Software for Graphics
The ability to be easily accessed or run by different systems and applications.
Software can be portable at the source code level, or at the object code (executable) level.
Most non-graphic programs are portable at the source code level, but must be recompiled to produce executable files for each separate system.
Most graphics programs are non-portable, even at the source level.
Programs written in the Java language, on the other hand, are portable both at the source code level and at the object code level.
This portability does require the presence and accessibility of a Java Virtual Machine (JVM) on the system.
Java virtual machines (software) are available for most popular systems, including Windows, Linux, and UNIX operating systems, and Intel and RISC processors.
Java also incorporates safety and security features not found in most other systems.
Java applets will run in almost all web browsers on almost all systems.
Java has a large standard graphics library which supports the creation, modification, and display of computer graphics.
Introduction to HTML
Blank HTML Pages
copyright 2004-2007, j.h.young, revised 1/12/07