[$125] IOS - Avatar doesn't get back to its original center position after zooming in and out

[lanitochka17]

If you haven’t already, check out our contributing guidelines for onboarding and email contributors@expensify.com to request to join our Slack channel!

---

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: 2024-12-10

Issue Owner

Current Issue Owner: @abdulrahuman5196

[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.
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>

[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]

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 is in the pinch gesture's onEnd handler in usePinchGesture.ts. Currently, the code only recenters the image in two scenarios:

1. When zooming below minimum scale
2. When zooming above maximum scale

However, it doesn't handle the case where the image is at a normal zoom level but offset from center. Here's the relevant code showing this limitation:

.onEnd(() => {
    if (zoomScale.get() < zoomRange.min) {
        // Handles underzooming but not general positioning
        pinchScale.set(zoomRange.min);
        zoomScale.set(withSpring(zoomRange.min, SPRING_CONFIG));
    } else if (zoomScale.get() > zoomRange.max) {
        // Handles overzooming but not general positioning
        pinchScale.set(zoomRange.max);
        zoomScale.set(withSpring(zoomRange.max, SPRING_CONFIG));
    } else {
        // No position correction happens here
        pinchScale.set(zoomScale.get());
    }
});

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

We should modify the onEnd handler to always reset the position to center when the gesture ends, regardless of the zoom level. 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:

  .onEnd(() => {
   // ... existing code ...
    if (zoomScale.get() < zoomRange.min) {
        // If the zoom scale is less than the minimum zoom scale, we need to set the zoom scale to the minimum
        pinchScale.set(zoomRange.min);
        zoomScale.set(withSpring(zoomRange.min, SPRING_CONFIG, triggerScaleChangedEvent));
    } else if (zoomScale.get() > zoomRange.max) {
        // If the zoom scale is higher than the maximum 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

What alternative solutions did you explore? (Optional)

N/A

Result

Screen.Recording.2024-12-09.at.8.43.08.PM.mov

[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

[JoshIri360]

Proposal

Updated

[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 Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

[abdulrahuman5196]

Proposal

Updated

The only change is that the code changed from the if check to else check. Why do think the new change would work? Not sure on how the new change in the proposal is expected to work.

[JoshIri360]

@abdulrahuman5196

Currently, recentering only happens in extreme cases:

.onEnd(() => {
    // Extreme case 1: Zoomed too far out
    if (zoomScale.get() < zoomRange.min) {
        pinchScale.set(zoomRange.min);
        zoomScale.set(withSpring(zoomRange.min, SPRING_CONFIG));
        // Image recenters here
    } 
    // Extreme case 2: Zoomed too far in
    else if (zoomScale.get() > zoomRange.max) {
        pinchScale.set(zoomRange.max);
        zoomScale.set(withSpring(zoomRange.max, SPRING_CONFIG));
        // Image recenters here
    } 
    // Normal case: No recentering happens
    else {
        pinchScale.set(zoomScale.get());
    }
});

The proposed change ensures recentering happens in all cases:

.onEnd(() => {
    // Extreme case 1: Zoomed too far out
    if (zoomScale.get() < zoomRange.min) {
        pinchScale.set(zoomRange.min);
        zoomScale.set(withSpring(zoomRange.min, SPRING_CONFIG));
    } 
    // Extreme case 2: Zoomed too far in
    else if (zoomScale.get() > zoomRange.max) {
        pinchScale.set(zoomRange.max);
        zoomScale.set(withSpring(zoomRange.max, SPRING_CONFIG));
    } 
    // Normal case: Now we also recenter here
    else {
        // Always recenter after any pinch gesture
        offsetX.set(withSpring(0, SPRING_CONFIG));
        offsetY.set(withSpring(0, SPRING_CONFIG));
        pinchScale.set(zoomScale.get());
    }
});

As shown in the video, this creates a more consistent experience because the avatar always returns to center after the user finishes their pinch gesture, regardless of whether they were doing an extreme zoom or just a normal interaction. I'll update the proposal to include these explanations to better illustrate the technical difference.

[JoshIri360]

Proposal

Updated