/*

     File: APLContinuousPushViewController.m

 Abstract: Provides the "Continuous Push + Collision" demo.

 Tapping in the view changes the angle and magnitude of the force. To 

 visually show the force vector on screen, a red arrow is drawn representing

 the angle and magnitude of this vector. The force is continuously applied 

 while the behavior is active, so we keep the vector line visible and just 

 update its size and rotation to match the vector.

  Version: 1.3

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 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

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 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

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 */

#import "APLContinuousPushViewController.h"

#import "APLDecorationView.h"

@interface APLContinuousPushViewController ()

@property (nonatomic, weak) IBOutlet UIView *square1;

@property (nonatomic, strong) UIDynamicAnimator *animator;

@property (nonatomic, strong) UIPushBehavior *pushBehavior;

@end

@implementation APLContinuousPushViewController

//| ----------------------------------------------------------------------------

- (void)viewDidAppear:(BOOL)animated

{

    [super viewDidAppear:animated];

    UIDynamicAnimator *animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];

    UICollisionBehavior *collisionBehavior = [[UICollisionBehavior alloc] initWithItems:@[self.square1]];

    // Account for any top and bottom bars when setting up the reference bounds.

    [collisionBehavior setTranslatesReferenceBoundsIntoBoundaryWithInsets:UIEdgeInsetsMake(self.topLayoutGuide.length, 0, self.bottomLayoutGuide.length, 0)];

    [animator addBehavior:collisionBehavior];

    UIPushBehavior *pushBehavior = [[UIPushBehavior alloc] initWithItems:@[self.square1] mode:UIPushBehaviorModeContinuous];

    pushBehavior.angle = 0.0;

    pushBehavior.magnitude = 0.0;

    [animator addBehavior:pushBehavior];

    self.pushBehavior = pushBehavior;

    self.animator = animator;

}

//| ----------------------------------------------------------------------------

//  IBAction for the Tap Gesture Recognizer that has been configured to track

//  touches in self.view.

//

- (IBAction)handlePushContinousGesture:(UITapGestureRecognizer*)gesture

{

    // Tapping in the view changes the angle and magnitude of the force. To

    // visually show the force vector on screen, a red arrow is drawn

    // representing the angle and magnitude of this vector. The force is

    // continuously applied while the behavior is active, so we keep the vector

    // line visible and just update its size and rotation to represent the

    // vector.

    CGPoint p = [gesture locationInView:self.view];

    CGPoint o = CGPointMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds));

    CGFloat distance = sqrtf(powf(p.x-o.x, 2.0)+powf(p.y-o.y, 2.0));

    CGFloat angle = atan2(p.y-o.y, p.x-o.x);

    distance = MIN(distance, 200.0);

    // Display an arrow showing the direction and magnitude of the applied force.

    [(APLDecorationView*)self.view drawMagnitudeVectorWithLength:distance angle:angle color:[UIColor redColor] forLimitedTime:NO];

    // These two lignes change the actual force vector.

    [self.pushBehavior setMagnitude:distance / 100.0];

    [self.pushBehavior setAngle:angle];

}

@end