Arctangent example

C4WorkSpace.m

//
// C4WorkSpace.m
//
// Created by Travis Kirton and Greg Debicki.
//

#import "C4WorkSpace.h"

@implementation C4WorkSpace {
    C4Shape *shape, *shape2;
}

-(void)setup {
    shape = [C4Shape rect:CGRectMake(0, 0, 200, 10)];
    shape.anchorPoint = CGPointMake(0.0,0.5);
    shape.center = self.canvas.center;
    shape.userInteractionEnabled = NO;
    [self.canvas addShape:shape];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    CGPoint p = [[touches anyObject] locationInView:self.canvas];
    CGFloat arctangent = [C4Math atan2Y:p.y-self.canvas.center.y X:p.x-self.canvas.center.x];
    shape.rotation = arctangent;
    event = event;
}

@end