Apple IIe - Page 20

20 Apple lie Users Handbook
Apple lie Video Display Formats
The lie can display the following four types of video output :
40-column text mode .
80-column text mode (with optional 80-column card).
Low-resolution graphics
(40 x 48 with 16 colors).
High-resolution graphics (280 x 192 with 6 colors).
In the text mode , the lie has the capability to display 24 lines with
40 or 80 columns per line. The characters in the 80 column mode
are only half as wide as those in the 40 column mode. For this
reason, the 80 column text mode generally cannot be used with a
regular color or B&W television set as the resultant output is so
blurred that i t' is unreadable . A high-resolution video monitor
must be used to obtain clear output in the 80-column text mode.
In the text mode , any of the 96 ASCII characters can be displayed
including lower and upper-case letters numbers , and symbols.
The text characters are generally displayed as white dots on a
black
background. However, text characters can also be display-
ed as black characters on a white background. This type of
display is known as the inverse format.
Each individual character is displayed on a matrix seven dots
wide by eight dots high. The character itself is only five dots
wide . This leaves one blank dot on either side of the character.
Therefore, a total of two rows of blank dots are allowed between
characters . With the exception of lowercase characters with
descenders characters are created seven dots high. This leaves
one blank line of dots between characters.
Two
different character sets are available in the text mode: the
primary character set and the alternative character set. The
characters themselves are identical in each character set. How-
ever, the format in which the characters are displayed differs.
The following formats are available:
normal - white dots on black background .
inverse - black dots on a white background .
flashing - alternating between normal and inverse.