Character Cell Sizes - Digital Equipment VT520 Programming Manual

Table 7–1 shows the default character cell widths and heights based on the
number of lines and columns on the screen.
Table 7–1 Character Cell Sizes
Cell Size
24 Lines/Screen
Width
Height
36 Lines/Screen
Width
Height
48 Lines/Screen
Width
Height
When you design a character, you should lay out a character cell on grid paper.
The little boxes on the grid paper represent pixels. You fill in the pixels that
make up the character. The next section shows an example of a character design.
You should design six versions of your character set to fit six different character
cell sizes. This means that there will be a version of your soft character set to fit
any combination of lines and columns available on the terminal:
2
24 lines 80 columns
2
24 lines 132 columns
2
36 lines 80 columns
2
36 lines 132 columns
2
48 lines 80 columns
2
48 lines 132 columns
Design your character set, then load six versions of the set, one for each possible
line/column combination. The terminal automatically selects which version of the
set to use, based on the current number of lines and columns on the screen.
The terminal's built-in fonts follow the guidelines in Table 7–2, which lists the
different guidelines for characters displayed with 24 lines, 36 lines, or 48 lines on
the screen. In all cases, the screen resolution is 800 by 400 pixels for 80 columns,
792 by 400 pixels for 132 columns. The pixel aspect ratio is 1:1.4.
You must design your characters to fit the cell. The terminal ignores any pixels
that are defined outside the cell. Also, you should include empty pixels on the
left or right side of the character cell to allow for space between characters.
Figure 7–2 shows an example of spacing for an uppercase D character with 24
lines on the screen. In this example, the character for the 80-column font has two
pixel columns reserved for spacing.
80 Columns
10 pixels
16
10
10
10
8
Character Sets
7.6 Soft Character Sets
132 Columns
6 pixels
16
6
10
6
8
Character Sets 7–7