(* Copyright (C) 1987 Jensen & Partners International *)
DEFINITION MODULE Graph; (* Basic graphics routines *)


(* Filling functions take a combination of two colors
   encoded as Color1 + NumColor * Color2 *)

(* Device independant routines
   provided as procedure variables
   (see below)

PROCEDURE GraphMode;

PROCEDURE TextMode;

PROCEDURE Plot(x,y: CARDINAL; Color: CARDINAL);
(* set a single pixel to given color *)

PROCEDURE Point(x,y: CARDINAL) : CARDINAL;
(* read a pixel of the screen *)

PROCEDURE HLine(x,y,x2: CARDINAL; FillColor: CARDINAL);
(* draw a horizontal line of given color (used for filling) *)


End of device dependant routines
*)

PROCEDURE Line(x1,y1,x2,y2: CARDINAL; Color: CARDINAL);
(* draw an arbitrary line in given color *)

PROCEDURE Circle(x0,y0,r: CARDINAL; c: CARDINAL);
(* centre x0,y0; radius r *)

PROCEDURE Disc(x0,y0,r : CARDINAL; FillColor: CARDINAL);
(* filled circle, centre x0,y0; radius r *)

PROCEDURE Ellipse ( x0,y0 : CARDINAL ;  (* center *)
                    a0,b0 : CARDINAL ;  (* semi-axes *)
                    c     : CARDINAL ;  (* color *)
                    fill  : BOOLEAN ) ; (* wether filled *)



PROCEDURE Polygon(n: CARDINAL; px,py: ARRAY OF CARDINAL; FillColor: CARDINAL);
(* filled polygon of n points *)


(*
   Initialization routines.
   Called to setup display output type.
*)

PROCEDURE InitCGA ;    (* Default *)
PROCEDURE InitEGA ;
PROCEDURE InitVGA ;
PROCEDURE InitHerc ;
PROCEDURE InitATT ;


TYPE
  PlotProc     = PROCEDURE ((* x *) CARDINAL,(* y *)CARDINAL,(* c *)CARDINAL);
  PointProc    = PROCEDURE ((* x *) CARDINAL,(* y *)CARDINAL) : CARDINAL ;
  HLineProc    = PROCEDURE ((* x *) CARDINAL,(* y *)CARDINAL,(* x2 *)CARDINAL,
                            (* FillColor *)CARDINAL);
VAR
  Width    : CARDINAL ;     (* x values are 0..Width-1  *)
  Depth    : CARDINAL ;     (* y values are 0..Depth-1  *)
  NumColor : CARDINAL ;     (* Colors are 0..NumColor-1 *)

(*
  procedure variables for device dependant routines
*)

  GraphMode,TextMode     : PROC ;
  Plot                   : PlotProc ;
  Point                  : PointProc ;
  HLine                  : HLineProc ;

(*
    Device specific constants and routines
    equivalent to the variables Width, Depth and NumColors
*)
PROCEDURE CGAGraphMode;
PROCEDURE CGATextMode;
PROCEDURE CGAPlot(x,y:CARDINAL;c:CARDINAL);
PROCEDURE CGAPoint(x,y:CARDINAL) : CARDINAL;
PROCEDURE CGAHLine ( x,y,x2 : CARDINAL; c:CARDINAL );
PROCEDURE EGAGraphMode;
PROCEDURE EGAPlot( x,y,c : CARDINAL);
PROCEDURE EGAPoint(x,y:CARDINAL) : CARDINAL;
PROCEDURE EGAHLine ( x,y,x2 : CARDINAL; c:CARDINAL );
PROCEDURE HercGraphMode;
PROCEDURE HercTextMode;
PROCEDURE HercPlot(x,y:CARDINAL;c:CARDINAL);
PROCEDURE HercPoint(x,y:CARDINAL) : CARDINAL;
PROCEDURE HercHLine ( x,y,x2 : CARDINAL; c:CARDINAL );
PROCEDURE ATTGraphMode;
PROCEDURE ATTPlot(x,y:CARDINAL;c:CARDINAL);
PROCEDURE ATTPoint(x,y:CARDINAL) : CARDINAL;
PROCEDURE ATTHLine ( x,y,x2 : CARDINAL; c:CARDINAL );
CONST
  VGAGraphMode = EGAGraphMode ;
  VGAPlot      = EGAPlot ;
  VGAPoint     = EGAPoint ;
  VGAHLine     = EGAHLine ;
  EGATextMode  = CGATextMode ;
  VGATextMode  = CGATextMode ;
  ATTTextMode  = CGATextMode ;

CONST
  CGAWidth           = 320 ;
  CGADepth           = 200 ;
  CGANumColor        = 4 ;
  EGAWidth           = 640 ;
  EGADepth           = 350 ;
  EGANumColor        = 16 ;
  VGAWidth           = 640 ;
  VGADepth           = 480 ;
  VGANumColor        = 16 ;
  HercWidth          = 720 ;
  HercDepth          = 348 ;
  HercNumColor       = 2 ;
  ATTWidth           = 640 ;
  ATTDepth           = 400 ;
  ATTNumColor        = 2 ;



END Graph.