Chapter 7
Coordinates, Windows, and Viewports

• World coordinates -- Problem-oriented

• Screen coordinates -- Of device in use.

• Normalized screen coordinates -- (0,0) and (1,1) at opposite corners of the screen.

• Window -- Visible rectangular region of the world. Boundaries are specified in world coordinates.

• Viewport - A region, within the screen, that displays a window. Boundaries are specified in
  • Screen coordinates

  • Normalized screen coordinates (trasformations between window and viewport coordinates are machine-independent)

• A window acts as a clip region only for future insertions.
• A window may have many viewports

  

7.1 Window to Viewport Transformation

T(x‘_min,y‘_min) ^. S(x‘_max-x‘_min x_max-x_min , y‘_max-y‘_min y_max-y_min ) ^. T(-x_min,-y_min)