Syntax10.Scn.Fnt
Syntax10b.Scn.Fnt
MODULE XYplane;  
(* Graphic output to screen, Input from keyboard, page 91, 100, 311 *)
IMPORT Display, MenuViewers, Oberon, TextFrames, Input;
CONST 
	max = 32768;  closed = 0;  displayed = 2;
	black = Display.black;  white = Display.white;  replace = Display.replace;
	erase* = 0;  draw* = 1; (* values for parameter mode in Dot *)
TYPE 
	XYframe = POINTER TO XYframeDesc;
	XYframeDesc = RECORD (Display.FrameDesc) END;
	F: XYframe;  V: MenuViewers.Viewer;
	bitmap: ARRAY max OF SET;
	X*, Y*, W*, H*: INTEGER;
PROCEDURE Modify(F: XYframe; VAR M: MenuViewers.ModifyMsg);
BEGIN
	IF (M.id = MenuViewers.extend) & (M.dY > 0) THEN
		Display.ReplConst(black, F.X, F.Y + F.H, F.W, M.dY, replace)
	END;
	IF M.Y < F.Y THEN
		Display.ReplConst(black, F.X, M.Y, F.W, F.Y - M.Y, replace)
	END;
	X := F.X;  Y := M.Y;  W := F.W;  H := M.H
END Modify;
PROCEDURE XYhandle*(F: Display.Frame; VAR M: Display.FrameMsg);
BEGIN
	WITH F: XYframe DO
		IF M IS Oberon.InputMsg THEN
			WITH M: Oberon.InputMsg DO
				IF M.id = Oberon.track THEN
					Oberon.DrawCursor(Oberon.Mouse, Oberon.Arrow, M.X, M.Y)
				END
			END
		ELSIF M IS MenuViewers.ModifyMsg THEN
			WITH M: MenuViewers.ModifyMsg DO
				Modify(F, M)
			END
		END
	END 
END XYhandle;
PROCEDURE Clear*;
VAR j: LONGINT;
BEGIN
	Display.ReplConst(black, F.X, F.Y, F.X + F.W, F.Y + F.H, replace);
	j := 0;  WHILE j < max DO  bitmap[j] := {}; INC(j) END
END Clear;
PROCEDURE Open*;
VAR menuF: TextFrames.Frame;  x, y: INTEGER;  
BEGIN
	IF V.state # displayed THEN
		Oberon.OpenTrack(Display.Left, 0);
		menuF := TextFrames.NewMenu("XY Plane", "System.Close");
		NEW(F);  F.handle := XYhandle;
		Oberon.AllocateUserViewer(Display.Left, x, y);
		V := MenuViewers.New(menuF, F, TextFrames.menuH, x, y)
	END;
	Clear
END Open;
PROCEDURE Dot*(x, y, mode: INTEGER);
VAR k, i, j: LONGINT;
BEGIN 
	IF (x >= F.X) & (x < F.X + F.W) & (y >= F.Y) & (y < F.Y + F.H) THEN
		k := LONG(y)*F.W + x;  i := k DIV MAX(SET);  j := k MOD MAX(SET);
		CASE mode OF
			  0: Display.Dot(black, x, y, replace); EXCL(bitmap[i], j)
			|1: Display.Dot(white, x, y, replace); INCL(bitmap[i], j)
		END
END Dot;
PROCEDURE IsDot*(x, y: INTEGER): BOOLEAN;
VAR k, i, j: LONGINT;
BEGIN
	IF (x >= F.X) & (x < F.X + F.W) & (y >= F.Y) & (y < F.Y + F.H) THEN
		k := LONG(y)*F.W + x;  i := k DIV MAX(SET);  j := k MOD MAX(SET);  
		IF j IN bitmap[i] THEN RETURN TRUE  ELSE RETURN FALSE END
	ELSE RETURN FALSE
END IsDot;
PROCEDURE Key*(): CHAR;
VAR ch: CHAR;
BEGIN  ch := 0X;
	IF Input.Available() > 0 THEN  Input.Read(ch)  END;
	RETURN ch
END Key;
BEGIN  
	NEW(F);  F.H := 0;  NEW(V);  V.state := closed; 
END XYplane.	(* Copyright M. Reiser, 1992 *)