code: def visual_border_width(self):
          
          render_to_doc =  \
              self.transforms.get_transform('document', 'visual')
  
          vec = render_to_doc.map([self.border_width, self.border_width, 0])
          origin = render_to_doc.map([0, 0, 0])
  
          visual_border_width = [vec[0] - origin[0], vec[1] - origin[1]]
  
          # we need to flip the y axis because coordinate systems are inverted
          visual_border_width[1] *= -1
  
          return visual_border_width
docs: The border width in visual coordinates