code: def set_linewidth(self, w):
          
          DEBUG_MSG("set_linewidth()", 1, self)
          self.select()
          if w>0 and w<1: w = 1
          GraphicsContextBase.set_linewidth(self, w)
          lw = int(self.renderer.points_to_pixels(self._linewidth))
          if lw==0: lw = 1
          self._pen.SetWidth(lw)
          self.gfx_ctx.SetPen(self._pen)
          self.unselect()
docs: Set the line width.