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1.4 Displaying the image and managing the screen

To begin with, it is necessary to specify the screen on which we wish to produce the image. Then, having defined a visualization mode and described the object, its graphical representation will appear on the screen.

To complete the lay-out, the user can define the portion of the visualization surface on which he/she wishes to produce the plot. The user can also define several visualization windows in which he/she will be able to plot independent objects.

To ensure independence between terminals, the image is produced conceptually on a type of virtual screen before being displayed. Consequently, using FORTRAN 3D, it is possible to write directly onto this surface to ensure that the lay-out of the image is desirable. Certain applications can only use this part of FORTRAN 3D.

Lastly, to facilitate the programming and improve the program's efficiency, FORTRAN 3D incorporates the possibility of dividing the screen into segments. The programmer can thus regroup certain parts of the image in the form of segments that he/she can either display or switch off, highlight or delete. This possibility is only effective if an appropriate graphics terminal is used.