Meonardo Meonardo - 1 year ago 99
Objective-C Question

Get the actual angle after the superview is rotated

I have 5 subviews(White) added to the superview(Gray), when I rotate the superview I want to know the angle(like 1 and 2) of each of the subview with the red circle.(the center of the subviews and the red circle are ON the same circle)

Start Position:
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Rotated Position:
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CRD CRD
Answer Source

From your comment you appear to want to determine the coordinates of the centres of your five circles for a given rotation. The centres will all lie on a circle. So your question boils down to what are the coordinates of a point on a circle of radius r for an angle θ. The parametric equations for a circle give you that:

x = r cos θ

y = r sin θ

The angle, θ, in these equations is measured in radians from the positive x-axis in an anti-clockwise direction. If your angle are in degrees you will find the M_PI constant for π useful as:

360 degrees = 2 π radians

The rest is simple math, take your angle of rotation to give you the angle for A (remembering to adjust for 0 being the x-axis and measuring anti-clockwise if needed), the other centres are multiples of 72 degrees (0.4 π radians) from this.

HTH