ios - UIBezierPath Rotation around a UIView's center -

i'm creating custom uiview, in implement draw(rect:) method drawing circle large width using uibezierpath, draw square on top (as shown in picture, don't consider colors or size). try creating rotated copies of square, match "settings" icon (picture 2, consider outer ring). last thing, need rotate square using cgaffinetransform(rotationangle:) problem rotation's center origin of frame, , not center of circle. how can create rotation around point in view?

as demonstration of @duncanc's answer (up voted), here drawing of gear using cgaffinetransforms rotate gear tooth around center of circle:

class gear: uiview {     var linewidth: cgfloat = 16     let boxwidth: cgfloat = 20     let toothangle: cgfloat = 45      override func draw(_ rect: cgrect) {          let radius = (min(bounds.width, bounds.height) - linewidth) / 4.0          var path = uibezierpath()         path.linewidth = linewidth         uicolor.white.set()          // draw circle         path.move(to: cgpoint(x: center.x + radius, y: center.y))         path.addarc(withcenter: cgpoint(x: center.x, y: center.y), radius: radius, startangle: 0, endangle: 2 * .pi, clockwise: true)         path.stroke()          // box gear tooth         path = uibezierpath()         let point = cgpoint(x: center.x - boxwidth / 2.0, y: center.y - radius)         path.move(to: point)         path.addline(to: cgpoint(x: point.x, y: point.y - boxwidth))         path.addline(to: cgpoint(x: point.x + boxwidth, y: point.y - boxwidth))         path.addline(to: cgpoint(x: point.x + boxwidth, y: point.y))         path.close()         uicolor.red.set()          // draw tooth every toothangle degrees         _ in stride(from: toothangle, through: 360, by: toothangle) {             // move origin center of circle             path.apply(cgaffinetransform(translationx: -center.x, y: -center.y))              // rotate             path.apply(cgaffinetransform(rotationangle: toothangle * .pi / 180))              // move origin original location             path.apply(cgaffinetransform(translationx: center.x, y: center.y))              // draw tooth             path.fill()         }     } }  let view = gear(frame: cgrect(x: 0, y: 0, width: 200, height: 200)) 

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here running in playground: