[$250] IOS - Avatar doesn't get back to its original center position after zooming in and out

[lanitochka17]

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Version Number: 9.0.70-2
Reproducible in staging?: Y
Reproducible in production?: Y
If this was caught on HybridApp, is this reproducible on New Expensify Standalone?: Y
If this was caught during regression testing, add the test name, ID and link from TestRail: https://expensify.testrail.io/index.php?/tests/view/5291133
Email or phone of affected tester (no customers): nathanmulugetatesting+2272@gmail.com
Issue reported by: Applause - Internal Team

Action Performed:

1. Open hybrid app
2. Upload a custom avatar for your profile
3. Open your self DM
4. Open the avatar to show in full screen
5. Pinch out to zoom and without releasing our finger pinch in to zoom out and position your fingers to the corner while zooming out and release your fingers

Expected Result:

The position of the avatar gets back to its original center position

Actual Result:

The avatar stays at the position it was released on and doesn't get back to the center

Workaround:

Unknown

Platforms:

Which of our officially supported platforms is this issue occurring on?

• Android: Standalone
• Android: HybridApp
• Android: mWeb Chrome
• iOS: Standalone
• iOS: HybridApp
• iOS: mWeb Safari
• MacOS: Chrome / Safari
• MacOS: Desktop

Screenshots/Videos

Add any screenshot/video evidence

Bug6683084_1733231204767.ScreenRecording_12-03-2024_15-58-36_1.1.mp4

View all open jobs on GitHub

Upwork Automation - Do Not Edit

• Upwork Job URL: https://www.upwork.com/jobs/~021863989062279850488
• Upwork Job ID: 1863989062279850488
• Last Price Increase: 2025-01-13

[melvin-bot]

Triggered auto assignment to @greg-schroeder (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details. Please add this bug to a GH project, as outlined in the SO.

[melvin-bot]

Job added to Upwork: https://www.upwork.com/jobs/~021863989062279850488

[melvin-bot]

Triggered auto assignment to Contributor-plus team member for initial proposal review - @abdulrahuman5196 (External)

[melvin-bot]

Upwork job price has been updated to $125

[ahmedkhan28]

Hi! I came across your job posting on Upwork regarding the avatar centering issue in your iOS app. After analyzing the problem where the avatar doesn't return to center after zoom gestures, I believe this can be fixed effectively through iterative solutions. I am a full time full stack iOS developer, designer and game developer at MagicHabits. This can be fixed in max 1-2 days.

Based on my experience with iOS gesture handling and UI animations, I've identified 5 potential approaches that could solve this:

Spring Animation Reset

swiftCopyUIView.animate(withSpringDamping: 0.8) {
avatarImageView.center = view.center
}

Velocity-Based Repositioning

swiftCopylet velocity = gesture.velocity(in: view)
let newCenter = calculatePosition(from: velocity)
animateToPosition(newCenter)

Smart Edge Detection

swiftCopyif !safeBounds.contains(avatar.frame) {
returnToCenter(animated: true)
}

Progressive Center Force

swiftCopylet centerForce = 1 - currentScale
let newCenter = interpolate(current: position,
target: center,
force: centerForce)

Physics-Based Boundaries

swiftCopylet behavior = UIAttachmentBehavior(item: avatarImageView)
animator.addBehavior(behavior)
Most natural but complex implementation
Recommended Approach:

I suggest implementing Solution #1 (Spring Animation Reset) first, then enhancing it with elements of Solution #4 (Progressive Center Force). This combination would:

Provide immediate improvement in UX
Feel natural and iOS-native
Be quick to implement and test
Allow for easy tuning of behavior

Let me know if you like it so I can submit a proposal on upwork!

[melvin-bot]

📣 @ahmedkhan28! 📣
Hey, it seems we don’t have your contributor details yet! You'll only have to do this once, and this is how we'll hire you on Upwork.
Please follow these steps:

1. Make sure you've read and understood the contributing guidelines.
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   Format:

Contributor details
Your Expensify account email: <REPLACE EMAIL HERE>
Upwork Profile Link: <REPLACE LINK HERE>

[ahmedkhan28]

Contributor details
Your Expensify account email: ahmedkhan850@gmail.com
Upwork Profile Link: www.upwork.com/agencies/1838604427293852717

[melvin-bot]

✅ Contributor details stored successfully. Thank you for contributing to Expensify!

[JoshIri360]

Edited by proposal-police: This proposal was edited at 2024-12-20 10:33:27 UTC.

Proposal

Please re-state the problem that we are trying to solve in this issue.

Avatar doesn't get back to its original center position after zooming in and out

What is the root cause of that problem?

The root cause of this problem is that recentering the avatar is only done if the zoom scale is less than the minimum zoom scale or more than the maximum zoom scale.

When zoomed past the minimum zoom, it recenters and adjusts the zoom:

overzoomed.mp4

When zoomed past the maximum zoom, it does the same (may be difficult to see here)

output.mp4

If it's not a maximum or minimum zoom, there is no recenter, this allows the user move the avatar in any direction without it recentering

Recording.at.2024-12-20.11.06.43.mp4

The line of code that helps the zoom recenter after minimum or maximum zoom can be found here:

App/src/components/MultiGestureCanvas/usePinchGesture.ts

Lines 164 to 168 in 207622d

	// If the content was "overzoomed" or "underzoomed", we need to bounce back with an animation
	if (pinchBounceTranslateX.get() !== 0 || pinchBounceTranslateY.get() !== 0) {
	pinchBounceTranslateX.set(withSpring(0, SPRING_CONFIG));
	pinchBounceTranslateY.set(withSpring(0, SPRING_CONFIG));
	}

What changes do you think we should make in order to solve the problem?

We should modify the onEnd handler to reset the position to center when the gesture ends, if it's not overzoomed or underzoomed. This ensures the avatar maintains its expected centered position after any pinch interaction.

The logic should be added in the else block where we handle normal zoom levels:

zoom scale, we need to set the zoom scale to the maximum
        pinchScale.set(zoomRange.max);
        zoomScale.set(withSpring(zoomRange.max, SPRING_CONFIG, triggerScaleChangedEvent));
    } else {
+         // Ensure image is centered
+         offsetX.set(withSpring(0, SPRING_CONFIG));
+         offsetY.set(withSpring(0, SPRING_CONFIG));
    
        // Otherwise, we just update the pinch scale offset
        pinchScale.set(zoomScale.get());
        triggerScaleChangedEvent();
    }
});

What specific scenarios should we cover in automated tests to prevent reintroducing this issue in the future?

N/A, It's a UI issue

What alternative solutions did you explore? (Optional)

N/A

Result

compressednormalxoom.mp4

[melvin-bot]

📣 @JoshIri360! 📣
Hey, it seems we don’t have your contributor details yet! You'll only have to do this once, and this is how we'll hire you on Upwork.
Please follow these steps:

1. Make sure you've read and understood the contributing guidelines.
2. Get the email address used to login to your Expensify account. If you don't already have an Expensify account, create one here. If you have multiple accounts (e.g. one for testing), please use your main account email.
3. Get the link to your Upwork profile. It's necessary because we only pay via Upwork. You can access it by logging in, and then clicking on your name. It'll look like this. If you don't already have an account, sign up for one here.
4. Copy the format below and paste it in a comment on this issue. Replace the placeholder text with your actual details.
   
   Format:

Contributor details
Your Expensify account email: <REPLACE EMAIL HERE>
Upwork Profile Link: <REPLACE LINK HERE>

[JoshIri360]

Contributor details
Your Expensify account email: aidelojejoshua@gmail.com
Upwork Profile Link: https://www.upwork.com/freelancers/~018bc4a19179469daa

[melvin-bot]

✅ Contributor details stored successfully. Thank you for contributing to Expensify!

[ahmedkhan28]

Submitted the proposal just now, thank you!

[greg-schroeder]

Next up is proposal review

[melvin-bot]

@greg-schroeder, @abdulrahuman5196 Huh... This is 4 days overdue. Who can take care of this?

[ahmedkhan28]

We had to have a contract before me solving it, right?

…

On Mon, 9 Dec 2024 at 2:42 PM, melvin-bot[bot] ***@***.***> wrote: @greg-schroeder <https://github.com/greg-schroeder>, @abdulrahuman5196 <https://github.com/abdulrahuman5196> Huh... This is 4 days overdue. Who can take care of this? — Reply to this email directly, view it on GitHub <#53471 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BACMSUPE6HB5SRTCJIZO6OL2EVQXXAVCNFSM6AAAAABS54WRMOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKMRXGQYTKMZZG4> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[abdulrahuman5196]

Hi, will review today

[greg-schroeder]

Thanks @abdulrahuman5196

[abdulrahuman5196]

@ahmedkhan28 / @JoshIri360 Kindly follow the proposal template for suggesting solutions as mentioned here https://github.com/Expensify/App/blob/main/contributingGuides/CONTRIBUTING.md#propose-a-solution-for-the-job

And on another not @JoshIri360 I tried your solution and its not fixing the issue. I am still able to repro the issue with your solution.

[abdulrahuman5196]

No pending proposal to review or approve yet

[abdulrahuman5196]

Will check the updated in my morning

[melvin-bot]

📣 It's been a week! Do we have any satisfactory proposals yet? Do we need to adjust the bounty for this issue? 💸

[melvin-bot]

@greg-schroeder, @abdulrahuman5196 Whoops! This issue is 2 days overdue. Let's get this updated quick!

[melvin-bot]

@greg-schroeder @abdulrahuman5196 this issue is now 4 weeks old, please consider:

• Finding a contributor to fix the bug
• Closing the issue if BZ has been unable to add the issue to a VIP or Wave project
• If you have any questions, don't hesitate to start a discussion in #expensify-open-source

Thanks!

[melvin-bot]

@greg-schroeder, @abdulrahuman5196 Still overdue 6 days?! Let's take care of this!

[melvin-bot]

📣 It's been a week! Do we have any satisfactory proposals yet? Do we need to adjust the bounty for this issue? 💸

[abdulrahuman5196]

Proposal

Updated

@JoshIri360 I still don't agree on the rootcause

The root cause of this problem is that recentering the avatar is only done if the zoom scale is less than the minimum zoom scale or more than the maximum zoom scale.

I am seeing this issue even on other normal zoom cases occasionally as well

[melvin-bot]

@greg-schroeder, @abdulrahuman5196 Eep! 4 days overdue now. Issues have feelings too...

[greg-schroeder]

Still awaiting viable proposals per the above

[melvin-bot]

📣 It's been a week! Do we have any satisfactory proposals yet? Do we need to adjust the bounty for this issue? 💸

[greg-schroeder]

What do you think @abdulrahuman5196 - raise bounty here?

[melvin-bot]

@greg-schroeder, @abdulrahuman5196 Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

[greg-schroeder]

I'll raise the bounty

[melvin-bot]

Upwork job price has been updated to $250

[greg-schroeder]

Updated bounty to generate more interest

[anboia]

Proposal

Please re-state the problem that we are trying to solve in this issue.

The avatar image does not get back to original position after composition of pinch and pan gestures, when leaving one of the fingers out of the canvas area.

What is the root cause of that problem?

Inadequate handling when a touch pointer leaves the screen. The pinch gesture is being interrupedt by the pinchEnabled state, when there is no more two fingers and the punch gesture is on course.

Explanation:

The pinch gesture is defined as follow, in usePinchGesture.ts:

const pinchGesture = Gesture.Pinch()
    .enabled(pinchEnabled)
    /// .......

The following part of the code disable the pinch gesture:

.onChange((evt) => {
    // Disable the pinch gesture if one finger is released,
    // to prevent the content from shaking/jumping
    if (evt.numberOfPointers !== 2) {
        runOnJS(setPinchEnabled)(false);
        return;
    }

When a touch pointer leaves the screen, the pinch gesture does not end properly, and the accumulated transformations are not finalized. Specifically on iOS, when a touch leaves the screen, the gesture may not trigger onEnd handlers, leading to incomplete gesture resolution.

What changes do you think we should make in order to solve the problem?

The simplest solution would be wrap the onEnd calback in a function handleGestureEnd, and call this function instead of runOnJS(setPinchEnabled)(false);. That would be enough to propper finish the pinch gesture. Also, remove the usage of .enabled(pinchEnabled) since it would not be needed.

Additional fixes:

1. This error is raised everytime the gesture canvas is displayed. By adding a 'worklet'; statement on each gesture callback. After fixing this, the error stops.

Some of the callbacks in the gesture are worklets and some are not. Either make sure that all calbacks are marked as 'worklet' if you wish to run them on the UI thread or use '.runOnJS(true)' modifier on the gesture explicitly to run all callbacks on the JS thread.

2. An error is preventing the correct update of the zoom: After zooming in beyond the limit, it does not zoom back:

App/src/components/MultiGestureCanvas/usePinchGesture.ts

Line 132 in 44d3a4f

if (zoomScale.get() >= zoomRange.min * ZOOM_RANGE_BOUNCE_FACTORS.min && zoomScale.get() <= zoomRange.max * ZOOM_RANGE_BOUNCE_FACTORS.max) {

A fix would be just replace zoomScale.get() with newZoomScale in the condition, what actually needs to compare if should update or not the zoomScale value.

Result

Video.2025-01-17.at.15.51.29.mp4

What specific scenarios should we cover in automated tests to prevent reintroducing this issue in the future?

NA