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ios 7 parallax effect in my view controller


ios 7 parallax effect in my view controller  using -'ios,objective-c,swift,parallax'

I'm developing an app for iOS 7 in Objective-C. I've got a screen in my app with a few buttons and a pretty background image. (It's a simple xib with UIButtons on top of a UIImageView.)

I was thinking that it'd be cool if those buttons had the parallax effect that the iOS 7 home screen has, so if you tilt the phone you could see the background.

How can I implement that effect in my own app?
    

asked Sep 29, 2015 by dhananjayksharma
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7 Answers

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With iOS 7, Apple introduced UIMotionEffect to add Motion effects that are related to the orientation of the user’s device. For example, to emulate the parallax effect on the home screen, you can use the subclass UIInterpolationMotionEffect, as explained here and here, just with a few lines of code.

Objective-C:

// Set vertical effect
UIInterpolatingMotionEffect *verticalMotionEffect = 
  [[UIInterpolatingMotionEffect alloc] 
  initWithKeyPath:@"center.y"
             type:UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis];
verticalMotionEffect.minimumRelativeValue = @(-10);
verticalMotionEffect.maximumRelativeValue = @(10);

// Set horizontal effect 
UIInterpolatingMotionEffect *horizontalMotionEffect = 
  [[UIInterpolatingMotionEffect alloc] 
  initWithKeyPath:@"center.x"     
             type:UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis];
horizontalMotionEffect.minimumRelativeValue = @(-10);
horizontalMotionEffect.maximumRelativeValue = @(10);

// Create group to combine both
UIMotionEffectGroup *group = [UIMotionEffectGroup new];
group.motionEffects = @[horizontalMotionEffect, verticalMotionEffect];

// Add both effects to your view
[myBackgroundView addMotionEffect:group];

Swift (Thanks to @Lucas):

// Set vertical effect
let verticalMotionEffect = UIInterpolatingMotionEffect(keyPath: "center.y",
type: .TiltAlongVerticalAxis)
verticalMotionEffect.minimumRelativeValue = -10
verticalMotionEffect.maximumRelativeValue = 10

// Set horizontal effect
let horizontalMotionEffect = UIInterpolatingMotionEffect(keyPath: "center.x",
    type: .TiltAlongHorizontalAxis)
horizontalMotionEffect.minimumRelativeValue = -10
horizontalMotionEffect.maximumRelativeValue = 10

// Create group to combine both
let group = UIMotionEffectGroup()
group.motionEffects = [horizontalMotionEffect, verticalMotionEffect]

// Add both effects to your view
myBackgroundView.addMotionEffect(group)

Also, you can find a bunch of libraries to do this easier or to add this functionality to older iOS versions:

answered Sep 29, 2015 by vimaldas2005
0 votes

Veducms solution can be a little shorter. The UIMotionEffectGroup for its x and y motion is obsolete if you add the the x and y-axis motionEffects separately.

UIInterpolatingMotionEffect *motionEffect;
motionEffect = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.x"
                                                               type:UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis];
motionEffect.minimumRelativeValue = @(-25);
motionEffect.maximumRelativeValue = @(25);
[bgView addMotionEffect:motionEffect];

motionEffect = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.y"
                                                               type:UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis];
motionEffect.minimumRelativeValue = @(-25);
motionEffect.maximumRelativeValue = @(25);
[bgView addMotionEffect:motionEffect];
answered Sep 29, 2015 by rolvyrf
0 votes

Translated to swift in case anyone is lazy. Please vote @veducm answer up if you found this useful

@IBOutlet var background : UIImageView!

func parallaxEffectOnBackground() {
    let relativeMotionValue = 50
    var verticalMotionEffect : UIInterpolatingMotionEffect = UIInterpolatingMotionEffect(keyPath: "center.y",
        type: .TiltAlongVerticalAxis)
    verticalMotionEffect.minimumRelativeValue = -relativeMotionValue
    verticalMotionEffect.maximumRelativeValue = relativeMotionValue

    var horizontalMotionEffect : UIInterpolatingMotionEffect = UIInterpolatingMotionEffect(keyPath: "center.x",
        type: .TiltAlongHorizontalAxis)
    horizontalMotionEffect.minimumRelativeValue = -relativeMotionValue
    horizontalMotionEffect.maximumRelativeValue = relativeMotionValue

    var group : UIMotionEffectGroup = UIMotionEffectGroup()
    group.motionEffects = [horizontalMotionEffect, verticalMotionEffect]

    self.background.addMotionEffect(group)
}
answered Sep 29, 2015 by abhi
0 votes
const static CGFloat kCustomIOS7MotionEffectExtent = 10.0; 

- (void)applyMotionEffects:(UIView *YOUR_VIEW) {
     if (NSClassFromString(@"UIInterpolatingMotionEffect")) {
         UIInterpolatingMotionEffect *horizontalEffect = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.x"
                                                                                                        type:UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis];
         horizontalEffect.minimumRelativeValue = @(-kCustomIOS7MotionEffectExtent);
         horizontalEffect.maximumRelativeValue = @( kCustomIOS7MotionEffectExtent);
         UIInterpolatingMotionEffect *verticalEffect = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.y"
                                                                                                      type:UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis];
         verticalEffect.minimumRelativeValue = @(-kCustomIOS7MotionEffectExtent);
         verticalEffect.maximumRelativeValue = @( kCustomIOS7MotionEffectExtent);
         UIMotionEffectGroup *motionEffectGroup = [[UIMotionEffectGroup alloc] init];
         motionEffectGroup.motionEffects = @[horizontalEffect, verticalEffect]; 
         [YOUR_VIEW addMotionEffect:motionEffectGroup];
     }
}
answered Sep 29, 2015 by tseetha
0 votes

UIMotionEffect provides a free parallax implementation on iOS 7.

http://www.teehanlax.com/blog/introduction-to-uimotioneffect/

https://github.com/michaeljbishop/NGAParallaxMotion lets you just set the parallax intensity.

answered Sep 29, 2015 by tushar2k6
0 votes

Here is an easy category to integrate the effect on iOs7+ :

NSString *const centerX = @"center.x";
NSString *const centerY = @"center.y";

//#define IS_OS_7_OR_LATER    ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)

@implementation UIView (TLMotionEffect)

- (void)addCenterMotionEffectsXYWithOffset:(CGFloat)offset {

//    if(!IS_OS_7_OR_LATER) return;
    if(floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) return;

    UIInterpolatingMotionEffect *xAxis;
    UIInterpolatingMotionEffect *yAxis;

    xAxis = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:centerX type:UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis];
    xAxis.maximumRelativeValue = @(offset);
    xAxis.minimumRelativeValue = @(-offset);

    yAxis = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:centerY type:UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis];
    yAxis.minimumRelativeValue = @(-offset);
    yAxis.maximumRelativeValue = @(offset);

    UIMotionEffectGroup *group = [[UIMotionEffectGroup alloc] init];
    group.motionEffects = @[xAxis, yAxis];

    [self addMotionEffect:group];
}

@end

https://github.com/jvenegas/TLMotionEffect

answered Sep 29, 2015 by manju bhargava
0 votes

Swift translation:

// Set vertical effect
let verticalMotionEffect = UIInterpolatingMotionEffect(keyPath: "center.y", type: .TiltAlongVerticalAxis)
verticalMotionEffect.minimumRelativeValue = -value
verticalMotionEffect.maximumRelativeValue = value

// Set vertical effect
let horizontalMotionEffect = UIInterpolatingMotionEffect(keyPath: "center.x", type: .TiltAlongHorizontalAxis)
verticalMotionEffect.minimumRelativeValue = -value
verticalMotionEffect.maximumRelativeValue = value

let group = UIMotionEffectGroup()
group.motionEffects = [horizontalMotionEffect, verticalMotionEffect]
self.motionEffect = group
self.addMotionEffect(group)
answered Sep 29, 2015 by deepak07.s

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