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
Input Devices
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).
Output Devices
Raster Devices
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.
Vector Devices
Plotters - good for vector graphics.
Oscilloscope - an early vector graphics output device.
Vector Graphics and Raster Graphics
vector 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.
raster graphics
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
Portability
portability
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.
Java
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.
