To make 16 uilabels and align them in circular path. - iphone

Question

NSMutableArray *views = [[NSMutableArray alloc]initWithCapacity:0];
for (NSInteger i = 0; i<16; i++)
{
UIView *circle = [[UIView alloc]init];
circle.backgroundColor = [UIColor clearColor];
UIImageView *circleImage = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 80, 80)];
circleImage.image = [UIImage imageNamed:#"circle"];
[circle addSubview:circleImage];
UILabel *labelInsideCircle = [[UILabel alloc]initWithFrame:CGRectMake(10, 10, 40, 40)];
labelInsideCircle.backgroundColor = [UIColor clearColor];
labelInsideCircle.textColor = [UIColor greenColor];
labelInsideCircle.font = [UIFont fontWithName:#"Helvetica" size:30.0];
labelInsideCircle.center = circleImage.center;
NSInteger int_ = [self getRandomNumber:0 to:(arrOfOptions.count-1)];
labelInsideCircle.text = [NSString stringWithFormat:#"%#",[arrOfOptions objectAtIndex:int_]];
labelInsideCircle.textAlignment = NSTextAlignmentCenter;
[arrOfOptions removeObjectAtIndex:int_];
[circle addSubview:labelInsideCircle];
[labelInsideCircle release];
[views addObject:circle];
[circle release];
[circleImage release];
}
/* Rotating circles with angles */
float curAngle = 0;
float incAngle = ( 360.0/(views.count) )*3.14/180.0;
CGPoint circleCenter = CGPointMake(380, 580); /* given center */
float circleRadius = 250; /* given radius */
for (UIView *view in views)
{
CGPoint viewCenter;
viewCenter.x = circleCenter.x + cos(curAngle)*circleRadius;
viewCenter.y = circleCenter.y + sin(curAngle)*circleRadius;
view.transform = CGAffineTransformRotate(view.transform, curAngle);
view.center = viewCenter;
[self.view addSubview:view];
curAngle += incAngle;
}
The problem is here the text of UILabel is also getting transformed, which is obvious. What I want is 16 circular views with labels on them without the label's text transformed. Can anyone please help me out with this ?

Answer 1

In this case, you just need to change their location coordinates, not rotate them.
NSMutableArray *views = [[NSMutableArray alloc] initWithCapacity:0];
for (NSInteger i = 0; i<16; i++)
{
UIView *circle = [[UIView alloc]init];
circle.backgroundColor = [UIColor clearColor];
UIImageView *circleImage = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 80, 80)];
circleImage.image = [UIImage imageNamed:#"circle"];
[circle addSubview:circleImage];
UILabel *labelInsideCircle = [[UILabel alloc]initWithFrame:CGRectMake(10, 10, 40, 40)];
labelInsideCircle.backgroundColor = [UIColor clearColor];
labelInsideCircle.textColor = [UIColor greenColor];
labelInsideCircle.font = [UIFont fontWithName:#"Helvetica" size:30.0];
labelInsideCircle.center = circleImage.center;
NSInteger int_ = arc4random()%[arrOfOptions count];
labelInsideCircle.text = [NSString stringWithFormat:#"%#",[arrOfOptions objectAtIndex:int_]];
labelInsideCircle.textAlignment = NSTextAlignmentCenter;
[arrOfOptions removeObjectAtIndex:int_];
[circle addSubview:labelInsideCircle];
[labelInsideCircle release];
[views addObject:circle];
[self.view addSubview:circle];
[circle release];
[circleImage release];
}
/* Rotating circles with angles */
float curAngle = 0;
float incAngle = ( 360.0/(views.count) )*3.14/180.0;
CGPoint circleCenter = CGPointMake(380, 580); /* given center */
float circleRadius = 250; /* given radius */
for (UIView *view in views)
{
CGPoint viewCenter;
viewCenter.x = circleCenter.x + cos(curAngle)*circleRadius;
viewCenter.y = circleCenter.y + sin(curAngle)*circleRadius;
//view.transform = CGAffineTransformRotate(view.transform, curAngle);
view.center = viewCenter;
[self.view addSubview:view];
curAngle += incAngle;
}
Some coding suggestions:
You can use arc4random() function if you don't have anything special in your own random number generator.
You can turn on ARC in xCode!

Answer 2

In a loop set their centers accordingly, don't rotate them nor their super view.
The following is not directly related to your question but may be helpful:
Aparaently you have got all the math available. I suggest to measure how much cpu time gets lost on the cos and sin etc. calls. If you find that significant then think about your algorithm. You will (most probably) find out that you call cos and sin hundrets or thousands of times for a limited number of angles.
You may then try it and find out that possible pre-calculations or just "caching and reusing" earlier results may save significant processing time.
Plus pre-calculating or caching of sinus would do. You can derrive cosinus values from sinus (and vice versa) by adding (or substracting respectively) an offset of pi/2 (or 90 degrees respectively) to the argument.
For similar tasks I was working with degrees (not radiants) and found out that I could not predict the angles but that a significant of full degrees (1°, 2°, 3°, ... and nothing in between) was exact enough for the job. Then I maintained an array of 360 sinus values and used that instead of calling the real function again and again. (Plus I only had to calculate 90 of them and mirrored the results of the other 270 degrees according to the nature of the sinus function) 180 floats is not too much of memory compared to the speed that I gained. Something like that can be suitable for you too. In your case your potenital agruments to sin and cos are limited to full-number multipilers of incAngle.
Which means there are only [views count] number of potential values each.