// FillStyle demonstrates the difference between even odd and non zero winding rule. func FillStyle(gc draw2d.GraphicContext, x, y, width, height float64) { sx, sy := width/232, height/220 gc.SetLineWidth(width / 40) draw2dkit.Rectangle(gc, x+sx*0, y+sy*12, x+sx*232, y+sy*70) var wheel1, wheel2 draw2d.Path wheel1.ArcTo(x+sx*52, y+sy*70, sx*40, sy*40, 0, 2*math.Pi) wheel2.ArcTo(x+sx*180, y+sy*70, sx*40, sy*40, 0, -2*math.Pi) gc.SetFillRule(draw2d.FillRuleEvenOdd) gc.SetFillColor(color.NRGBA{0, 0xB2, 0, 0xFF}) gc.SetStrokeColor(image.Black) gc.FillStroke(&wheel1, &wheel2) draw2dkit.Rectangle(gc, x, y+sy*140, x+sx*232, y+sy*198) wheel1.Clear() wheel1.ArcTo(x+sx*52, y+sy*198, sx*40, sy*40, 0, 2*math.Pi) wheel2.Clear() wheel2.ArcTo(x+sx*180, y+sy*198, sx*40, sy*40, 0, -2*math.Pi) gc.SetFillRule(draw2d.FillRuleWinding) gc.SetFillColor(color.NRGBA{0, 0, 0xE5, 0xFF}) gc.FillStroke(&wheel1, &wheel2) }