The main areas where computer graphics is used are
Business Graphics
Scientific Graphics or Visualisation
Solid Modelling
VLSI design
Animation
CAD/CAM
Image Processing
Architectural design
Pretty Pictures
Computer Graphics uses the X-Y coordinate system =
Cartesian. Any point P = (x,y). Normally only 1 quadrant is
used ie (+x,+y) but where does screen sit?
For example a Gigi Graphics terminal (normally) sits in lower quadrant yet always has +ve coordinates. Similarly for an X workstation.
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Fig. 1.13 : Cartesian Coordinate System
1) What orientation is the screen?
2) What are maximum coordinates available?
ie physical maximum in inches-mm etc
or logical maximum in coordinate points.
3) What happens if (x,y) > (maxx,maxy)?
Physically or logically?
We must know the answers to these questions if we are to be
intimate with the devices ie write routines to drive the device.
We will initially look at output and input devices and then at
the X Window System and later look at writing our own device drivers for a simple graphics package.