Dont complain it anymore as it is normal to have and yet to improve. here's what anandtech say:
On iOS 10 Apple added the ability to interrupt certain animations. They've also made significant changes to how UIKit handles animations, allowing for better transitions between two animations and the ability to reverse an animation. I briefly covered these in my review of iOS 10. One of the areas where Apple has deployed these features is opening and closing applications. In the past, you were forced to wait for the app opening animation to finish before you could return to the home screen, which was quite bothersome if you accidentally opened an application that took a while to load its initial ViewController. This animation can now be interrupted, allowing you to cancel the opening of the application instantly by pressing the home button. The iPhone 7 and 7 Plus also have a special feature when closing applications. If you keep your finger on the home button and press it a second time after pressing to close the app, you can override the app closing and transition to the recent apps screen.
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App closing animation on iPhone 7
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Recent apps animation on iPhone 7
Being able to transition directly into recent apps is an interesting feature enabled by Apple's new home button, but the implementation is imperfect in its current form. The first issue is that it actually introduces a momentary stutter in the app closing animation. This stutter occurs at the point where it's no longer possible to cancel the closing of the app and move to the recent apps screen, and it comes as a consequence of Apple altering the timing functions used for the animation to enable the feature. It also causes strange motions when you open the recent apps menu, as even if you tap the home button twice in quick succession, the tweaked response of the new home button will always be faster than your finger clicking a second time. This means that you always see the start of the app closing animation before the recent apps animation starts, giving a different animation than you'll see on other iOS devices. I actually went through the animations frame by frame to create the images above. Apple is working to improve both of these issues, and ultimately it will come down to improving how transitions between animations are handled, as well as altering the timing function for the animations to prevent the areas where frames are dropped.
While the two issues above are more like animation bugs than performance problems, I think it's worth mentioning that even on the iPhone 7 with iOS 10's scrolling performance optimizations there are still a number of areas where strange frame drops and stutters can occur. For example, the performance in the Music app is just a complete and utter disaster, and it has been since iOS 7. Other areas just have inconsistent and random performance issues, like dropped frames when swiping and scrolling widgets, or when first bringing up 3D Touch quick actions, or when swiping between locations in the Weather app. I'm certainly not the first tech journalist to bring these issues up, and perhaps the most apt description I've seen is that the tiny bugs and stutters end up being death by a thousand cuts.
On iOS 10 Apple added the ability to interrupt certain animations. They've also made significant changes to how UIKit handles animations, allowing for better transitions between two animations and the ability to reverse an animation. I briefly covered these in my review of iOS 10. One of the areas where Apple has deployed these features is opening and closing applications. In the past, you were forced to wait for the app opening animation to finish before you could return to the home screen, which was quite bothersome if you accidentally opened an application that took a while to load its initial ViewController. This animation can now be interrupted, allowing you to cancel the opening of the application instantly by pressing the home button. The iPhone 7 and 7 Plus also have a special feature when closing applications. If you keep your finger on the home button and press it a second time after pressing to close the app, you can override the app closing and transition to the recent apps screen.
App closing animation on iPhone 7
Recent apps animation on iPhone 7
Being able to transition directly into recent apps is an interesting feature enabled by Apple's new home button, but the implementation is imperfect in its current form. The first issue is that it actually introduces a momentary stutter in the app closing animation. This stutter occurs at the point where it's no longer possible to cancel the closing of the app and move to the recent apps screen, and it comes as a consequence of Apple altering the timing functions used for the animation to enable the feature. It also causes strange motions when you open the recent apps menu, as even if you tap the home button twice in quick succession, the tweaked response of the new home button will always be faster than your finger clicking a second time. This means that you always see the start of the app closing animation before the recent apps animation starts, giving a different animation than you'll see on other iOS devices. I actually went through the animations frame by frame to create the images above. Apple is working to improve both of these issues, and ultimately it will come down to improving how transitions between animations are handled, as well as altering the timing function for the animations to prevent the areas where frames are dropped.
While the two issues above are more like animation bugs than performance problems, I think it's worth mentioning that even on the iPhone 7 with iOS 10's scrolling performance optimizations there are still a number of areas where strange frame drops and stutters can occur. For example, the performance in the Music app is just a complete and utter disaster, and it has been since iOS 7. Other areas just have inconsistent and random performance issues, like dropped frames when swiping and scrolling widgets, or when first bringing up 3D Touch quick actions, or when swiping between locations in the Weather app. I'm certainly not the first tech journalist to bring these issues up, and perhaps the most apt description I've seen is that the tiny bugs and stutters end up being death by a thousand cuts.
