/*

     File: APLCollisionsGravitySpringViewController.m

 Abstract: Provides the "Collisions + Gravity + Spring" demonstration.

  Version: 1.3

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 */

#import "APLCollisionsGravitySpringViewController.h"

#import "APLDecorationView.h"

@interface APLCollisionsGravitySpringViewController ()

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

//! The view that displays the attachment point on square1.

@property (nonatomic, weak) IBOutlet UIImageView *square1AttachmentView;

//! The view that the user drags to move square1.

@property (nonatomic, weak) IBOutlet UIImageView *attachmentView;

@property (nonatomic, strong) UIDynamicAnimator *animator;

@property (nonatomic, strong) UIAttachmentBehavior *attachmentBehavior;

@end

@implementation APLCollisionsGravitySpringViewController

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

- (void)viewDidLoad

{

    [super viewDidLoad];

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

    UIGravityBehavior *gravityBeahvior = [[UIGravityBehavior alloc] initWithItems:@[self.square1]];

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

    CGPoint anchorPoint = CGPointMake(self.square1.center.x, self.square1.center.y - 110.0);

    UIAttachmentBehavior *attachmentBehavior = [[UIAttachmentBehavior alloc] initWithItem:self.square1 attachedToAnchor:anchorPoint];

    collisionBehavior.translatesReferenceBoundsIntoBoundary = YES;

    // These parameters set the attachment in spring mode, instead of a rigid

    // connection.

    [attachmentBehavior setFrequency:1.0];

    [attachmentBehavior setDamping:0.1];

    // Visually show the attachment point.

    self.attachmentView.center = attachmentBehavior.anchorPoint;

    self.attachmentView.tintColor = [UIColor redColor];

    self.attachmentView.image = [self.attachmentView.image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];

    // Visually show the attachment point.

    self.square1AttachmentView.center = CGPointMake(50.0, 50.0);

    self.square1AttachmentView.tintColor = [UIColor blueColor];

    self.square1AttachmentView.image = [self.square1AttachmentView.image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];

    // Visually show the connection between the attachment points.

    [(APLDecorationView*)self.view trackAndDrawAttachmentFromView:self.attachmentView toView:self.square1 withAttachmentOffset:CGPointZero];

    [animator addBehavior:attachmentBehavior];

    [animator addBehavior:collisionBehavior];

    [animator addBehavior:gravityBeahvior];

    self.animator = animator;

    self.attachmentBehavior = attachmentBehavior;

}

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

//  IBAction for the Pan Gesture Recognizer and Tap Gesture Recognizer that have

//  been configured to track touches in self.view.  (Both types of gesture

//  recognizers are used so that square1AttachmentView is repositioned

//  immediately in response to a new touch, instead of waiting for that touch

//  to be recognized as a drag.)

//

- (IBAction)handleSpringAttachmentGesture:(UIGestureRecognizer*)gesture

{

    [self.attachmentBehavior setAnchorPoint:[gesture locationInView:self.view]];

    self.attachmentView.center = self.attachmentBehavior.anchorPoint;

}

@end