I'm using CGAffineTransformMakeRotation
to rotate a UIView
inside an animation block, and I want to rotate it counterclockwise for 180º
.
However when I put
myView.animateWithDuration(0.5)
myView.transform = CGAffineTransformMakeRotation(CGFloat(-M_PI))
it still rotates clockwise. What's confusing me is that if I write "manually" the value of M_PI
, it works as expected
// this will rotate counterclockwise
myView.transform = CGAffineTransformMakeRotation(CGFloat(-3.14159265358979))
Why this behavior?
Edit: added I'm using an animation block
As I stated in my first comment and as Segii already wrote: the animation will take the shortest distance between where it's value is at now and where it is trying to go. The best solution imho is to use
CABasicAnimation
for forcing a counterclockwise rotation:This will rotate it by 180 counter clockwise in one go.
The angle you specify in the last line + the
fromValue
is the starting angle -> 0. And then the rotation will go the distance(toValue - fromValue) = 0 - M_PI = - M_PI
-> counter clockwise 180 degree rotation.