Turbo Prolog

7 Tutorial V: Seeing Through
Turbo Prolog's Windows
Turbo Prolog allows you to incorporate windows in your programs (in full color if you
have the necessary hardware) and have full access to DOS. Before introducing Turbo
Prolog's first-class windowing capabilities, this chapter describes how to determine the
screen attribute values that will be used in window commands to determine the colors
both inside a given window and for the window frame (if there is one).
The chapter concludes with two exciting illustrations of the potential of Turbo Prolog's
windowing features (an arcade style "shoot-em-up" game and a word guessing game)
and then gives a few simple examples of how to interface your Turbo Prolog programs
with DOS.
SETTING THE SCREEN DISPLAY ATTRIBUTES
Turbo Prolog allows you to control such screen display characteristics as inverse video,
underlining and colors. This information is passed to standard predicates via an attribute
value which, among other things, determines the color of the characters (the foreground)
and the color behind the characters (the background). It is possible to give
attributes for single characters or for a whole screen area.
If your computer has a Monochrome Display Adapter, display attribute values are
calculated as follows:
• Choose the integer representing the desired foreground and background combination
from Table 7- I.
• Add I if you want characters to be underlined in the foreground color.
• Add 8 if you want the white part of the display to be in high intensity.
• Add 128 if you want the character to blink.
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