[Bug] Every Other Page are Gray Pages(PDF Issue)

[derzz]

Hi,

I'm trying to convert a manga from PDF to EPub and every time I convert, every other page in the epub file contains a page filled with gray. I'm using a Kobo Clara HD with Manga Mode, Stretch/Upscale, and Cropping Mode with the power at 1.00x enabled. Is this a bug or is there an option that I can enable to get rid of this issue?

Eg. Every page has the actual manga content like so:

But then a gray page like this appears:

And this pattern repeats for the whole ePub file.

[axu2]

If you open the epub on a PC do you still see the gray pages? The pdf might just have small gray images...

Unzip the epub and look in the images folder.

[derzz]

So on Calibre and when unzipping the epub, the gray pages are still there. I'm looking at the pdf and there doesn't seem to have small gray images in there other than the manga being black and white.

[axu2]

Are pages being replaced with gray? Or are additional gray pages being added?

[derzz]

Additional gray pages are being added.

[axu2]

Hmmm, my suspicion is that it's a problem with the source file. Are you able to obtain a CBZ instead (which can be unzipped as well)? Or an image folder? Can you test with just a folder of random .jpgs to see if you still get it? Or upload the source file here, or at least a couple pages?

[derzz]

So when I obtain the CBZ, it still is producing the same issues. The issue isn't here with a random JPG folder. Attached are some pages of the PDF, let me know if you need more information. Even testing the pdf with some pages attached still produces the gray pages.
よつばと! 第01巻_removed.pdf

[axu2]

I'll test myself soon. In the meantime, are you on the latest stable version 5.6.2?

[derzz]

Yes, I’m on the latest stable version 5.6.2. From: Alex Xu ***@***.***> Sent: Saturday, June 17, 2023 8:48 PM To: ciromattia/kcc ***@***.***> Cc: Michael Xie ***@***.***>; Author ***@***.***> Subject: Re: [ciromattia/kcc] [Bug] Every Other Page are Gray Pages (Issue #540) I'll test myself soon. In the meantime, are you on the latest stable version 5.6.2? — Reply to this email directly, view it on GitHub<#540 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AK4OK3GKSGHP5YW4EPH7Q5LXLZF4ZANCNFSM6AAAAAAZCMFOX4>. You are receiving this because you authored the thread.Message ID: ***@***.******@***.***>>

[axu2]

A single gray pixel is being generated between pages.

The pdf file must have stray single gray pixels between pages... Are you able to get a better source?

[derzz]

Sorry, I don't have a better source for this :(

Is there a way to delete these files, I'm fine if I have to manually do it, but if I manually delete each single gray pixel file, how would I repackage the image files into an epub?

[axu2]

I would try another program to extract the images out of the pdf. And then use the extracted file in KCC.

If you feel brave try editing pdfjpgextract.py

[axu2]

Can you test #546 @derzz

I was testing the sizes of the images in pdf and got this. But this is obviously a very small test case.

And this is very hacky, please fix up the PR when you finish testing with comments.

Alternatively, there's probably a better way to extract images in 2023, that code hasn't been touched in like 10 years probably.

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And please change the title to reflect that's it's a pdf issue

[derzz]

Sorry, but what should I do with #546? I have the release version right now and there's no python file for me to edit in the release. Can you elaborate on what I should do to test this PR?