Opening footnote target in large notes chapters can run out of memory during indexing

[eduardo-svg]

Device

X4

Affected Version

1.3.3

Build Variant

tiny

EPUB Optimization

No / Not Applicable

Cache State

All of the above

Describe the Bug

On CrossInk, following a footnote link in heavily annotated EPUB chapters can cause the device to show Indexing for a long time and then fail with a memory error. This is not a case where the footnotes list is missing. The failure happens after selecting/following a footnote, while CrossInk is trying to open/index the target notes chapter.

I reproduced/observed this with the attached (compressed) EPUB.

The issue happens when following footnotes in at least:

• Scylla And Charybdis
• Circe

This issue does not happen in CrossPoint 1.3.0 or 1.4.0 RC4.

Steps to Reproduce

1. Open EPUB.
2. Navigate to chapter "Scylla and Charybdis" or "Circe"
3. Follow the first footnote on the first page.

Expected Behavior

Following a footnote link should open the selected note, or at least index only what is needed to navigate to/render that note.

Relevant Log Output/Screenshots

[uxjulia]

Can you try the latest pre-release to see if it helps: https://github.com/uxjulia/CrossInk/releases

[eduardo-svg]

The Release Candidate switched the notes chapter to Balanced automatically and successfully resolved this issue.

[eduardo-svg]

@uxjulia I did some messing around with some fonts and flashed back and forth between the RC and the CrossPoint nightly, and just now switched back to this 1.3.4 RC. For some reason, it's failing to lay out the same footnotes chapter on any of the 3 rendering modes that it successfully rendered with Balanced earlier when I initially closed this issue.

[uxjulia]

@uxjulia I did some messing around with some fonts and flashed back and forth between the RC and the CrossPoint nightly, and just now switched back to this 1.3.4 RC. For some reason, it's failing to lay out the same footnotes chapter on any of the 3 rendering modes that it successfully rendered with Balanced earlier when I initially closed this issue.

Try clearing book cache?

[eduardo-svg]

@uxjulia That didn't help, unfortunately, and neither did toggling any of the styling settings.

[uxjulia]

@uxjulia That didn't help, unfortunately, and neither did toggling any of the styling settings.

Try turning off embedded styles

[uxjulia]

Try this version of your EPUB. I optimized it with an optimizer I'm working on that automatically breaks down epubs with large chapters into smaller sections to make it easier for the device to handle. I was able to open the footnotes.

James Joyce - Ulysses - Annotated Edition (Alma Classics Evergreens).epub.zip

Your book had a LOT of footnotes and large chapters, a bad combination for a device like this. Had to get creative and break the book down into smaller chunks for the device to handle.

[eduardo-svg]

Unfortunately this optimized version did not work for me for the footnotes chapter corresponding to the "Scylla and Charybdis" chapter.

Interestingly, the original EPUB works fine in CrossPoint, so I would have assumed that "Balanced" would be able to lay it out the same way (I think I read that Balanced is a similar rendering scheme to CP's default rendering), but no luck even when set to Light.

I'm not an expert but I'm going to try to do some testing on my end to see if I can pinpoint the exact failure mode here. I'll report back hopefully by tomorrow evening.

[uxjulia]

The fact that it did open it once with balanced mode tells me that the device at one point had the optimum amount of free contiguous memory and was able to open it, so it's possible, it just needs the ideal state of free blocks of memory. Think of it like Tetris. If all the blocks fit together, and there's all that open free space above you, you have a lot of freedom to move around and time to do things. But when you place the blocks haphazardly leaving a bunch of random space... it gets harder to place blocks. That's kind of how the memory works on this device right now. Random actions take up memory space and it's not always nice and uniform. Then when something needs a defined amount of space to do something and doesn't have it... it just fails.

Hoping in later versions of Crosspoint and Crossink to improve this.