✨ Improve Error Handling and Image Conversion in removeBackground Method

[enisit]

This PR enhances the removeBackground function within the iOS implementation of the ReactNativeBackgroundRemover package. The main goal is to improve error handling and stability during background removal by avoiding forced unwrapping and improving image conversion.

Key Changes:

1. Error Handling Improvements:

   • Added proper checks and guard statements to prevent crashes due to nil values. This ensures the app won’t crash when an invalid image URL or a failure in loading the image occurs.
   • Clear error messages are returned using the promise rejection system in case of failure during various stages (URL validation, image loading, segmentation results, etc.).

2. Improved Image Processing:

   • Used CIContext to convert CIImage to CGImage before generating a UIImage, ensuring better compatibility and avoiding crashes on certain devices.
   • Added a scaling check for the mask image to avoid up-scaling when the mask dimensions are smaller than the original image dimensions.

3. File Handling Enhancements:

   • Changed the file-saving logic to ensure the output image is saved as a PNG to preserve transparency.
   • Improved the temporary file path generation by appending the correct .png file extension.

Detailed Changes:

• Replaced forced unwrapping of URL and CIImage with guard statements to handle potential failure gracefully.
• Added a check to prevent up-scaling the mask when the mask image dimensions are smaller than the original image.
• Improved the conversion of the final CIImage to UIImage by using a CGImage intermediary, ensuring compatibility on all devices.
• Added specific error codes and messages for each failure point in the background removal process.

Benefits:

• This patch increases the robustness of the app by preventing potential crashes due to improper image handling and segmentation results.
• Users with devices experiencing crashes during the image conversion process should experience improved stability.
• Better file-saving mechanism ensures the final output preserves transparency, leading to higher quality results for users.

Affected Files:

• packages/react-native-background-remover/ios/ReactNativeBackgroundRemover.swift

[atlj]

LGTM Thank you so much for sending this!

[carlosmellado]

Had to go back to 0.2.0 because on this version removing background was very very unstable and on 0.2.0 was working a lot better. 😭

[atlj]

Had to go back to 0.2.0 because on this version removing background was very very unstable and on 0.2.0 was working a lot better. 😭

@carlosmellado that's pretty interesting, could you share some more context? What was unstable? Did you observe any unexpected crashes or performance issues?

[carlosmellado]

Not crashing but the results of removing background on iOS were very different than the version before. On this new version was not working as expected, like removing parts that not are the background or removing parts of the person in front.
Going back to the previous version resolved those issues and removing background works perfect

[enisit]

@carlosmellado our QA reported the same issue. Here is new PR that should solve it. @atlj please check it out.

[atlj]

@enisit @carlosmellado FYI, I just published this fix with 0.3.1