DEFINITION MODULE tvg;

(* tigr graphics backend for the tv toolkit.

   It drives the same view tree into an off-screen tigr bitmap instead of an
   ANSI terminal: tv keeps building the cell buffer, tvg renders those cells
   with tigr's font and turns tigr input into tv events.  Only programs that
   call InitGfx need to link tigr/OpenGL; the terminal apps stay tigr-free.

   Build (from the tvision-m2 directory):
       gm2 -fiso -I. -I../modula2 -c tvg.mod
   Link an application with:
       ... tv.o tvg.o ../modula2/tigr.o ../modula2/helper.o -lGL -lX11
*)

FROM tv IMPORT Event;

PROCEDURE InitGfx (title : ARRAY OF CHAR; cols, rows : INTEGER) : BOOLEAN;
PROCEDURE Done;
PROCEDURE Finish;                     (* tv.DrawTree + blit to the window *)
PROCEDURE ReadEvent (VAR e : Event) : BOOLEAN;
PROCEDURE Closed () : BOOLEAN;        (* window close / Esc requested *)
PROCEDURE CellW () : INTEGER;
PROCEDURE CellH () : INTEGER;

END tvg.