code: func (imd *IMDraw) Circle(radius, thickness float64) {
  	if thickness == 0 {
  		imd.fillEllipseArc(pixel.V(radius, radius), 0, 2*math.Pi)
  	} else {
  		imd.outlineEllipseArc(pixel.V(radius, radius), 0, 2*math.Pi, thickness, false)
  	}
  }
docs: // Circle draws a circle of the specified radius around each Pushed point. If the thickness is 0,
  // the circle will be filled, otherwise a circle outline of the specified thickness will be drawn.