Turbo Prolog

makewindow( ... )
shiftwindow( ... )
removewindow( ... )
clearwindow( ... )
window_str( ... )
window_attr( ... )
Also useful in this connection is the cursor positioning standard predicate
cursor( ... )
We'll now consider each predicate, starting with makewindow.
makewindow(WNo,ScrAttr,FrameAttr,Header,Row,Col,Height,Width)
The predicate makewindaw defines an area of the screen as a window. All parameters
except Header must be integers. Header must be a string or symbol, and it is used as a
title in the upper frame line. Windows are identified by a number (WNa) which is used
to select which on-screen window is active. If FromeAttr is greater or less than zero, a
border is drawn around the defined area (i.e., the window is framed) in the color
specified by that attribute. Once defined, the window is "cleared" to the background
color and the cursor is moved to its topmost left corner.
The row and column positions of the top left corner of the window-relative to the
whole screen-are specified by parameters Raw and Cal respectively, and Height and
Width give the dimensions of the window. Raw, Cal, Height and Width should correspond
to the size of the display. Typically, display size is 25 rows of 80 characters, but
this can be changed with the graphics standard predicate (see Chapter 8). Here's an
example use of makewindaw:
makewindow(1,7,135,IIMy first window ll ,1,20,L;,3L;)
Here, makewindaw specifies window number I, with a black and white display. A border
will be drawn (FromeAttr is 135) with the header "My first window" and the window
itself will be 4 rows high, 34 columns wide and be positioned with the top left
corner at row I, column 20 of the screen (note that rows and columns are numbered
from 0 onwards).
On the other hand
makewindow(2,7,135,lIcount the rows ll ,8,20,19,3L;)
will result in the error message
the parameters in makewindow are illegal
since a window with height 19 is impossible if positioned starting from row 8 (8+ 19 >
25 I). Notice also that if Height and Width are bound to 10 and 20 respectively, the
actual display area of the window will be 8 rows and 18 columns if the window is
framed (i.e., FromeAttr is bound to a non-zero value), since the frame will then occupy a
total of two rows and two columns.
Tutorial V: Seeing Through Turbo Prolog's Windows 79