Presentation space
The presentation space is a data structure that contains an element for each row and column position in the session window (but not including the last row of the session window, which is used for the Operator Information Area). The size of the presentation space depends on the size of the session window. For example, if the session window has 80 rows and 25 columns, then the size of the presentation space is 80 * 24 = 1920.
The position of the elements in the presentation space corresponds
serially to the row and column positions in the session window, reading
from left to right, top to bottom. For example, if the session window
has 80 rows and 25 columns, then:
Figure 1. Correspondence of row and column location
in the session window to the position in the presentation space
Row of Column of Corresponds to
Session Session element at this
Window: Window: position in PS:
1 1 1
1 2 2
1 3 3
...
1 80 80
2 1 81
2 2 82
2 3 83
...
24 79 1919
24 80 1920
Z and I Emulator for Web uses the presentation space to store the characters
that are to be displayed in the session window. Each element in the
presentation space is used to store one character (and information
about that character, such as intensity). For example, if the string Message appears
at row 1 and column 1 of the session window, then:
Figure 2. Layout when 'Message' appears
in row 1, column 1
Row of Column of Corresponds Character
Session Session to element stored in
Window: Window: at this pos- this element:
ition in PS:
1 1 1 M
1 2 2 e
1 3 3 s
1 4 4 s
1 5 5 a
1 6 6 g
1 7 7 e
Although you normally will not need to use them, Table 1 show the formulas for calculating various
values. The meanings of the symbols used in these formulas is as follows:
- row - A row location in the session window
- col - A column location in the session window
- pos - A position in the presentation space
- NUMROWS - The number of rows in the session window, not including the last row used for the Operator Information Area (OIA).
- NUMCOLS - The number of columns in the session window.
Value: | Formula for calculating: |
---|---|
Size of the PS |
|
row |
|
col |
|
pos |
|