23.  WINDOWS



GFA-windows


GFA-Basic has four "easy" windows for not too complicated jobs. Draw an 
imaginary cross on the screen. The intersection of the two lines is 
determined by the coordinates in 'OPENW n,x,y'. If you show more than one 
GFA-window on the screen, you should realize that resizing one window 
automatically changes the size of the other three windows as well. Use the 
AES window-commands if you need independent (GEM-)windows.


The four GFA-windows reserve the top line for the menu-line of a pulldown 
menu. If you use your own GEM-windows, you should protect the menu-line 
yourself, e.g. with 'OPENW 0'.


The GFA-windows are numbered 1 - 4 by GFA-Basic. Let's call this the 
window-index of a GFA-window. A window also has a number that's used by 
GEM. Let's call this the window-handle of the GEM-window. In a listing you 
can spot a window-index easily because the number is preceded by '#'. 
Except after OPENW:

     OPENW 1                  ! open GFA-window #1 
     OPENW #1,x,y,w,h,a       ! also opens GFA-window #1

The first command is used after some manipulation of the WINDTAB-
parameters. The second command changes these parameters directly, so you 
can ignore WINDTAB.


A standard-method for the use of one GFA-window looks like this:

     TITLEW #1," Title "      ! automatically centered
     INFOW #1,"Information"   ! left justified
     (...)                    ! adapt WINDTAB-parameters for GFA-window #1
     OPENW 1                  ! or use OPENW #1 with parameters
     CLEARW #1
     (...)
     CLOSEW #1
     CLOSEW 0                 ! see paragraph 'CLOSEW'



CLOSEW


If you have opened a window in your program, always use 'CLOSEW 0' before 
returning to the editor. Otherwise you won't be able to work normally in 
Direct Mode, although you can also type 'CLOSEW 0' in Direct Mode in order 
to restore everything to normal again. In a compiled program you have to 
avoid 'CLOSEW 0', because TOS will complain that too many files are open 
if you do use this command. No, I don't know why.


If you use the AES window-commands, always call WIND_CLOSE(handle) before 
WIND_DELETE(handle). Or use 'CLOSEW handle'.



TITLEW


You can clear a title with:

     TITLEW #n," "

Don't use "" instead of " ", or you won't be able to move the window 
afterwards!



CLEARW


After 'CLEARW #n' all visible areas of the GFA-window with index n are 
cleared, without activating the window. GFA uses WIND_UPDATE and WIND_GET 
for this command. 'CLEARW n' both clears and activates the GEM-window with 
handle n.