How To Create a Rotating Wheel Control with UIKit - objective-c

Question

Hi I'm trying to create a Rotation Wheel in iOS and I found this fantastic tutorial
How to Create a Rotation Wheel Control
and it is very nice and complete, but in this case the selected object is in the left and need the object in the right.
So I'm wondering if somebody knows what I need to change in order to select the rigth side
Well in the example we can see in the endtrackingWithTouch Event the following code
// 1 - Get current container rotation in radians
CGFloat radians = atan2f(container.transform.b,container.transform.a);
NSLog(#"Radians %f", radians);
// 2 - Initialize new value
CGFloat newVal = 0.0;
// 3 - Iterate through all the sectors
for (SMSector *s in sectors) {
// 4 - Check for anomaly (occurs with even number of sectors)
if (s.minValue > 0 && s.maxValue < 0) {
if (s.maxValue > radians || s.minValue < radians) {
// 5 - Find the quadrant (positive or negative)
if (radians > 0) {
newVal = radians - M_PI;
} else {
newVal = M_PI + radians;
}
currentSector = s.sector;
}
}
// 6 - All non-anomalous cases
else if (radians > s.minValue && radians < s.maxValue) {
newVal = radians - s.midValue;
currentSector = s.sector;
}
}
Doing the Math for radians and making some comparing the min and max in the sectors we get the selected sector also if I change (CGFloat radians = atan2f(container.transform.b,container.transform.a);) for CGFloat radians = atan2f(container.transform.d,container.transform.c); I'm able to get the sector from the bottom

Answer 1

I think you can simply put your wheel in another view and rotate this view one PI. Something like this:
UIView *testView = [[UIView alloc]initWithFrame:CGRectMake(10, 80,300, 300)];
SMRotaryWheel *wheel = [[SMRotaryWheel alloc] initWithFrame:CGRectMake(0, 0,300, 300)
andDelegate:self
withSections:5];
[testView addSubview:wheel];
testView.transform = CGAffineTransformMakeRotation(M_PI);
[self.view addSubview:testView];