Finding a sublayers position on the screen after several CATransforms?

My iPhone app has a mainView. added as a sublayer to this MainView is CircleView. CircleView rotates as the phone turns and tilts as the phone tilts, using 3 concatenated CATransform3D transforms. DotView is added as a sublayer to CircleView. After all these transoforms, I have no easy (or apparent) way of knowing the coordinates of dotView in the mainView coordinate system.

I also have another view, squareView, added to mainview as well. I do know the coordinates of squareView in mainView's coordinate system.

I want to use Quartz 2D to draw a line between a dotView an开发者_开发技巧d a squareView. How do I find out out the coordinates of squareView in order to draw a line between the two?

Thanks.

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You probably want to look at the presentationLayer property of the layer in question.