IOS how to screen coordinates of the center of rotation of a draw characters

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For example, using NSString's drawAtPoint in (50,50) to 45 degree rotation drawn "characters." How to do?

Reply:
You can use UILabel
Reply:
Connected, set about the transformation matrix
label.transform = CGAffineTransformMakeRotation (45);
Reply:
drawAtPoint put together this method there are some ways to know facie description