FOREIGN DEFINITION MODULE Cursor;
(*
     CURSOR.DEF - Provides some basic cursor manipulations, e.g. hiding
                  and displaying the cursor, changing it's shape and getting
                  the attributes of the current cursor.
 
     Initial Release : 08-Aug-94
                       Philip Sinfield - Programming Languages & Systems
                                         Group - GPM 
*)

IMPORT IMPLEMENTATION FROM "cursor.obj";

FROM Types IMPORT BYTECARD;      
(*
     Note : The use of BYTECARD is important as the low level BIOS routines
            return byte sized results (i.e. half 16 bit registers)
*) 

(* ************************************************************************ *)
    
PROCEDURE Hide ();
(*   Hides the cursor from view 
     Pre : A visible cursor exists
     Post: Cursor is hidden from display
*)

(* ************************************************************************ *)
    
PROCEDURE Restore ();
(*   Restore the cursor to the screen 
     Pre : Cursor is not visible
     Post: Cursor is made visible
*)

(* ************************************************************************ *)
    
(*  
     The next two procedures are dependent on the graphics hardware of
     an individual PC.  The values for "start" and "end" (0 -20H) are for
     VGA & SVGA hardware.  If VGA or SVGA hardware is not being used, then
     the scan line limits will need to be obtained from relevant technical
     documents.
*)

(* ************************************************************************ *)
    
PROCEDURE SetShape (start : BYTECARD; end : BYTECARD);
(*   Sets the shape of the cursor 
     Pre : A visible cursor exists
           0 <= start <= 020H
           0 <=  end  <= 01fH
     Post: Cursor shape is set by scan line "start" and
           scan line "end".  
           If start = 20H then cursor is "hidden"
*)

(* ************************************************************************ *)
    
PROCEDURE GetShape (VAR start : BYTECARD; VAR end : BYTECARD);
(*   Returns the size of the current cursor                 
     Pre : A visible cursor exists
     Post: Current cursor shape is defined by scan line "start" and
           scan line "end".  
           0 <= start <= 020H
           0 <=  end  <= 01fH
           If start = 20H then cursor is "hidden"
*)

(* ************************************************************************ *)
    
PROCEDURE GetAttribute (VAR ch : CHAR; VAR bg : BYTECARD;
                                       VAR fg : BYTECARD;
                                       VAR h  : BYTECARD;
                                       VAR b  : BYTECARD);
(*   Returns the character at the cursor and its attributes
     Pre : TRUE
     Post: ch is the character at the cursor
           bg is the background colour -> 00H - Black
                                          01H - Blue
                                          02H - Green
                                          03H - Cyan
                                          04H - Red
                                          05H - Magenta
                                          06H - Brown
                                          07H - White
           fg is the foreground colour -> 00H - Black
                                          01H - Blue
                                          02H - Green
                                          03H - Cyan
                                          04H - Red
                                          05H - Magenta
                                          06H - Brown
                                          07H - White
                                          08H - Grey
                                          09H - Bright Blue
                                          0aH - Bright Green
                                          0bH - Bright Cyan
                                          0cH - Bright Red
                                          0dH - Bright Magenta
                                          0eH - Yellow
                                          0fH - Bright White
          h is the highlight attribute -> 1 - Bright
                                          0 - Normal
          b is the blink attribute     -> 1 - Blinking
                                          0 - No Blink
*)

END Cursor.