Loading page per page option for iBooks?

[momoha]

Hi,

I’m making a fixed-layout with CSS3 animations and some javascript. I have some issues with it on iBooks; it crashes when the book is opened.

Someone told me it is possible to load each page by itself, page per page, instead of loading all of the pages as soon as the book is opened.

Any informations on that? I’ve been searching but couldn’t find anyting.

Thanks!

[Toxaris]

It is probably not the size that is the culprit. I suspect faulty coding. Does it validate? Try it without the javascript.

[momoha]

Originally Posted by Toxaris

It is probably not the size that is the culprit. I suspect faulty coding. Does it validate? Try it without the javascript.

Oh, I forgot to mention that on my iPad it’s working perfectly. The problem is happening on another iPad. It’s also working perfectly on Readium.

Also, it does validate.

This is what made us think that the issue doesn’t come from the code, but from something else.

[JSWolf]

Originally Posted by momoha

Oh, I forgot to mention that on my iPad it’s working perfectly. The problem is happening on another iPad. It’s also working perfectly on Readium.

Also, it does validate.

This is what made us think that the issue doesn’t come from the code, but from something else.

What version iOS are you using and on what iPad? Also, what version iOS and what version iPad is this other iPad? An iPad 1 won't work the same as any other iPad as it's stuck with iOS 5 and has less memory to run apps. Also the iPad 1 has an older version of iBooks and it might not work with your book.

The iPad 2 also is different then newer iPads as it only has 512MB of ram where the newer iPads all have 1GB (Ipad Air 2 has 2GB). So this book could be too memory intensive for anything below an iPad 3.

If you have an iPad Air 2, then maybe your book needs more then 1GB to load all at once.

We won;t have any idea until you tell us what iPads are being used for testing.

Oh and specifying multiple as your devices doesn't help at all when you ask questions like this.

[momoha]

Ok so actually the device with problems is an iPhone 6 with iBooks 4.1.1.

This morning, we were able to see 4 pages before it crashed, but it was very slow, lagging.

We have other books of the same kind (with animations) and on the same iPhone, there’s no issue...

By the way, I didn’t see the point of writing which devices I own considering our books have to work on as many devices as possible anyways...

[JSWolf]

Originally Posted by momoha

Ok so actually the device with problems is an iPhone 6 with iBooks 4.1.1.

This morning, we were able to see 4 pages before it crashed, but it was very slow, lagging.

We have other books of the same kind (with animations) and on the same iPhone, there’s no issue...

By the way, I didn’t see the point of writing which devices I own considering our books have to work on as many devices as possible anyways...

But if you do say what devices you are suing, someone might know why it works on yours and not another. he more information you put out there, the better chance of someone coming up with a solution.

[dgatwood]

Originally Posted by momoha

Ok so actually the device with problems is an iPhone 6 with iBooks 4.1.1.

This morning, we were able to see 4 pages before it crashed, but it was very slow, lagging.

Are you using CSS animation on margins and/or position, by some chance? Moving large raster images?

[JSWolf]

Do you perhaps have an iPad Air 2 which has 2GB of system ram?

[momoha]

I really don’t get it. I did many tests, and at some point the book always crash. Here’s what I tested:

• Without javascript
• Without animations
• With all the CSS sheets empty
• Without the images
• Without the fonts

And I don’t have an iPad air...

[odedta]

Did you try to update your iPad and reinstall iBooks? if that doesn't work i'm afraid you'll have to post some code :/

[dgatwood]

Originally Posted by momoha

I really don’t get it. I did many tests, and at some point the book always crash. Here’s what I tested:

• Without javascript
• Without animations
• With all the CSS sheets empty
• Without the images
• Without the fonts

And I don’t have an iPad air...

Back in iOS 7, I kept running into a bad kernel memory leak that caused apps to crash en masse if the device had been up and running without a reboot for 30+ days (depending on usage). The problem might still happen in iOS 8. So if you haven't tried shutting the device completely off and booting it back up, try that first.

Short of something like that, I'd be surprised if the problem were caused by a lack of RAM, particularly given that the device that is failing has at least as much RAM as the one that is working.

With that said, if you want to try to experiment with RAM reduction, the iBooks rendering engine (WebKit) always has just a single HTML file in memory at any given point in time, discarding the previous one as it passes a page boundary. Of course, there's also a back/forward cache and various other caches, so that's not precisely true, but either way, the less you put in a given HTML file, the less should be in memory at any given moment, and those caches are thrown away if you run out of memory, so they shouldn't be a problem.

I mean, I suppose it is possible that iBooks might be doing something silly like extracting the entire Zip archive in RAM, but I doubt it.


A couple more questions:

1. Does it fail reliably when you advance to any particular page? Or away from any particular page?

2. Could you paste in the crash log file? (It might not be of any help, but then again, it might.)