Performance issues with GFLiveScannerViewController

gualtierofrigerio / GFLiveScanner

Import this package to perform live scanning of barcodes, QR codes and OCR.

MIT License

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Performance issues with GFLiveScannerViewController #2

Closed AnthoPakPak closed 1 year ago

AnthoPakPak commented 1 year ago

Hey, thanks for the library!

I've successfully integrated GFLiveScannerViewController into my project. Unfortunately, I've then discovered that my UI was getting slow and unresponsive after a few seconds. After trying again the Demo app, I've made the same observations.

To reproduce:

Open Demo app
Click OCR VC
Target some text with camera (it seems like more text causes more unresponsiveness)
After a few seconds, you will notice it's harder to pull down the view controller to dismiss
If you keep scanning text, it becomes less and less responsive

Have you faced this issue too? I've checked the code but can't find where I could patch the issue. I bet it's a matter of moving the text recognition from main thread to a background thread.

Any help is appreciated 🤗

gualtierofrigerio commented 1 year ago

Thanks for your comment and your interest in the library :)

I didn't use the OCR much at the time I shared this (more the barcode), at least not in live mode so I don't remember if I had performance issues. Having a quick look at the code now I think a possibility could also be avoiding queueing too many requests in GFOcrHelper, I don't remember exactly the logic but I think I implemented a list of requests to process them one at a time. Maybe too many requests are made and this is a problem so a threshold could be set, like no more than X requests process per second and you drop the others. I don't know when I'll have time to test this approach but it may be a possibility to explore.

AnthoPakPak commented 1 year ago

Hey, thanks a lot for your quick answer!

Thanks to your insights, I've took another look and managed to improve performances by:

Moving VNRecognizeTextRequest to a background thread (this is the main thing, allowing to not block the UI)
Removing the queuing of requests, I don't need it in my use case

It's now behaving well enough for my use. Thanks for your work on this!

gualtierofrigerio commented 1 year ago

thanks for the feedback, maybe I could change something in order to have the queue or requests as an option instead of being the default and of course a different thread for some of the operations, I thought it was already like that but it wasn't...