Save as PDF by Default

[samuelbeek]

What is the problem

I think we should save the documents as PDF by default, because:

• All other scan apps do this (Dropbox, Scanbot).
• Hardware Scanners do it.
• People are most likely to "scan" documents.
  • PDF is the standard for scanned documents - there's no clear data on this, but if you read this and take into consideration that all actual scanners using PDF as well, I think there's a good case to be made.
  • Most documents contain text, JPEG makes text unreadable.

[jcampbell05]

I second this, whats best way of doing this ?

[Boris-Em]

PDFKit makes this pretty easy, but it's only supported on iOS 11+. Maybe we could drop support of iOS 10 for this specific feature @samuelbeek, @jcampbell05?

[julianschiavo]

I think this feature should be opt in by the creators of the app who use the framework - for example, my usage for WeScan would not use PDFs.

[samuelbeek]

@Boris-Em I agree that we could make it an iOS 11 only feature.

[Boris-Em]

Good point @justJS!

[jcampbell05]

Some companies will be dropping iOS 10 support soon so I think there is little value trying to port PDF to iOS 10. So I'm happy for it to be just iOS 11.

[julianschiavo]

I also agree it's ok for PDF support to be iOS 11 only, but I really want WeScan to keep iOS 10 support for now. While it's only a small percent, it's still more users.

[jcampbell05]

@justJS I'm just meaning to keep PDF iOS11 only and not the framework :) WeScan should support iOS 10 at least for little while longer

[julianschiavo]

Yeah, just making sure we're clear :smile:

[julianschiavo]

Thoughts on PSPDFKit? Supports iOS 10, has some other benefits

Note: I don't know about pricing or anything, just saw it around

[jcampbell05]

That costs so a no go for me but I recalled that iOS always had lower level PDF graphics as Quartz was based on PDF. So we have the CGPDFContextCreate methods (Since iOS 2.0) we can use to easily write a basic PDF with the images into a file.

This should be okay as I think PDFKit was mainly introduced to handle other features beyond the rendering which the Quartz APIs didn't handle (annotations etc) which we won't likely need for a scanner.

So I think we should just use this API for iOS 10 and 11. The advantage is it can also export to JPG or PNG as well (Assuming you create correct context) https://developer.apple.com/documentation/coregraphics/cgpdfcontext

[julianschiavo]

👍 What does everyone think about how it should be implemented? I'm thinking, as I said, a host app setting, but any other ideas? Perhaps we could provide both the PDF and typical image back to the host app?

[Boris-Em]

Agreed. We could add a new scannedPDF property to ImageScannerResults. This way users get both a UIImage and a PDF back. Let's just make sure first that creating the pdf is very fast.

[julianschiavo]

👍 Since there's changes to the ImageScannerResults (the auto rotation) in #41, I can start working on this after that's merged (should be soon).

Edit: Well I might as well just check this out now, I have some free time. I'll update with how it goes.

[julianschiavo]

Hey, I've done some work on this but am waiting for #80 to be merged (it includes changes to ImageScannerResults)

[jcampbell05]

@justJS now #80 is merged, did we merge the PDF stuff in ?

[julianschiavo]

I've started work: #133

[julianschiavo]

133 is done and ready for review 🎉

(it's a breaking change as it renames variables in ImageScannerResults)

EDIT: PDFs are supported on all versions of iOS! PDFKit wasn't suitable for this purpose so I'm using lower-level CoreGraphics APIs.

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