UNIT NAME:  GRAPH3

  DECLARATION:  USES Graph3;

      PURPOSE:  Provides compatibility with version 3.x graphics, to include
                Turtle Graphics, Graphics Windows, Colors, Plotting and
                Drawing.

    CONSTANTS:
                    Const
                       North = 0;
                       East  = 90;
                       South = 180;
                       West  = 270;



                         PROCEDURES and FUNCTIONS
 ------------------------------------------------------------------------

  Arc               Draws an arc using the specified parameters
  Back              Moves the turtle backwards a given distance
  Circle            Draws a circle using the specified parameters
  ClearScreen       Clears the active window and homes the turtle
  ColorTable        Defines a color translation table
  Draw              Draws a line between specified points in a spcified
                    color
  FillPattern       Fills a rectangle with a specific pattern, using a
                    specified color
  FillScreen        Fills the active window with the specified color
  FillShape         Fills the area of a shape with a specified color
  Forwd             Moves the turtle forward a given distance
  GetDotColor       Returns the color value of the dot at a specified
                    location
  GetPic            Copies the contents of an region of the screen into
                    a buffer  (See PutPic)
  GraphBackGround   Sets the background color of the active window
  GraphColorMode    Sets the graphics mode to 320x200 color
  GraphMode         Sets the graphics mode to 320x200 Black-and-White
  GraphWindow       Defines a area of the screen as the active window
  Heading           Returns the current heading of the turtle
  HideTurtle        Hides the turtle from view
  HiRes             Sets the graphics mode to 640x200 high-resolution
  HiResColor        Selects the color to be used for drawing in high
                    reolution graphics
  Home              Places the turtle in the home position
  NoWrap            Disables 'wrapping' for the turtle
  Pallette          Activates a specified color palette
  Pattern           Defines an 8x8 pattern for FillPattern
  PenDown           Positions the 'Pen' down so that any movements cause
                    the turtle to draw
  PenUp             Positions the 'Pen' up so that the tuttle can be
                    moved without drawing
  Plot              Plots a point at a specified set of coordinates, in a
                    specified color.
  PutPic            Copies the contents of a previously saved buffer; use
                    with GetPic
  SetHeading        Turns the turtle toward a specified heading (angle)
  SetPenColor       Sets the color used for the turtles pen
  SetPosition       Moves the turtle to a set of coordinates without drawing
                    a line
  ShowTurtle        Unhides the turtle, making it visible.
  TurnLeft          Turns the turtle left (counter-clockwise)
  TurnRight         Turns the turtle right (clockwise)
  TurtleDelay       Sets the delay between the steps of the turtle
  TurtleThere       Checks if the turtle is visible, and in the active window
  TurtleWindow      Defines an area of the screen as the active Turtle-
                    Graphics window
  Wrap              Enables window 'wrapping' when the turtle passes past
                    the boundaries of the active window
  XCor              Returns the X-coordinate of the turtle
  YCor              Returns the Y-coordinate of the turtle


   Full descriptions can be found in the Turbo Pascal v3.x reference manual