(self, llx, lly, urx, ury)
Set up a user defined coordinate-system.

        Arguments:
        llx -- a number, x-coordinate of lower left corner of canvas
        lly -- a number, y-coordinate of lower left corner of canvas
        urx -- a number, x-coordinate of upper right corner of canvas
        ury -- a number, y-coordinate of upper right corner of canvas

        Set up user coodinat-system and switch to mode 'world' if necessary.
        This performs a screen.reset. If mode 'world' is already active,
        all drawings are redrawn according to the new coordinates.

        But ATTENTION: in user-defined coordinatesystems angles may appear
        distorted. (see Screen.mode())

        Example (for a TurtleScreen instance named screen):
        >>> screen.setworldcoordinates(-10,-0.5,50,1.5)
        >>> for _ in range(36):
        ...     left(10)
        ...     forward(0.5)
Set up a user defined coordinate-system.
Set up a user defined coordinate - system .
def setworldcoordinates(self, llx, lly, urx, ury):
        """Set up a user defined coordinate-system.

        Arguments:
        llx -- a number, x-coordinate of lower left corner of canvas
        lly -- a number, y-coordinate of lower left corner of canvas
        urx -- a number, x-coordinate of upper right corner of canvas
        ury -- a number, y-coordinate of upper right corner of canvas

        Set up user coodinat-system and switch to mode 'world' if necessary.
        This performs a screen.reset. If mode 'world' is already active,
        all drawings are redrawn according to the new coordinates.

        But ATTENTION: in user-defined coordinatesystems angles may appear
        distorted. (see Screen.mode())

        Example (for a TurtleScreen instance named screen):
        >>> screen.setworldcoordinates(-10,-0.5,50,1.5)
        >>> for _ in range(36):
        ...     left(10)
        ...     forward(0.5)
        """
        if self.mode() != "world":
            self.mode("world")
        xspan = float(urx - llx)
        yspan = float(ury - lly)
        wx, wy = self._window_size()
        self.screensize(wx-20, wy-20)
        oldxscale, oldyscale = self.xscale, self.yscale
        self.xscale = self.canvwidth / xspan
        self.yscale = self.canvheight / yspan
        srx1 = llx * self.xscale
        sry1 = -ury * self.yscale
        srx2 = self.canvwidth + srx1
        sry2 = self.canvheight + sry1
        self._setscrollregion(srx1, sry1, srx2, sry2)
        self._rescale(self.xscale/oldxscale, self.yscale/oldyscale)
        self.update()
def setworldcoordinates ( self , llx , lly , urx , ury ) : if self . mode ( ) != "world" : self . mode ( "world" ) xspan = float ( urx - llx ) yspan = float ( ury - lly ) wx , wy = self . _window_size ( ) self . screensize ( wx - 20 , wy - 20 ) oldxscale , oldyscale = self . xscale , self . yscale self . xscale = self . canvwidth / xspan self . yscale = self . canvheight / yspan srx1 = llx * self . xscale sry1 = - ury * self . yscale srx2 = self . canvwidth + srx1 sry2 = self . canvheight + sry1 self . _setscrollregion ( srx1 , sry1 , srx2 , sry2 ) self . _rescale ( self . xscale / oldxscale , self . yscale / oldyscale ) self . update ( )