Increase/decrease fontsize of EPUB in EPUBNavigationController using UIKit (No SwiftUI)

[pattyzamsal]

Hello mate!

I have been trying to increase/decrease fontsize of EPUB but I'm not getting a good result.

First, let me explain to you how I'm initializing the EPUBNavigationController

   let preferences = EPUBPreferences(fontSize: 1.0, scroll: false, theme: .dark)
   let config = EPUBNavigatorViewController.Configuration(preferences: preferences)
   epubNavigatorViewController = try EPUBNavigatorViewController(
            publication: publication,
            initialLocation: locator,
            config: config,
            httpServer: GCDHTTPServer.shared
   )
   epubNavigatorViewController.delegate = self
   addChild(epubNavigatorViewController)
   bookEPUBView.addSubview(epubNavigatorViewController.view)
   epubNavigatorViewController.view.frame = bookEPUBView.bounds
   epubNavigatorViewController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
   epubNavigatorViewController.didMove(toParent: self)

Then, I'm doing the increase of the font after the user presses a button with the following code:

  let preferences = EPUBPreferences(fontSize: 4.0, theme: .dark) 
   epubNavigatorViewController.submitPreferences(preferences)

As it is indicated in this guide: https://github.com/readium/swift-toolkit/blob/develop/Documentation/Guides/Navigator%20Preferences.md

But this doesn't work, could you please help me? Maybe, I'm missing something but it is very difficult to understand or find a good example of how I need to do it.

Thanks in advance!

[mickael-menu]

This looks correct, do you have the same issue using this book? childrensliterature.epub.zip.

Also, does changing the theme in the EPUBPreferences work?

Some books use absolute font sizes and you can't change it unless you set publisherStyles to false in EPUBPreferences.

[pattyzamsal]

Yes, changing the theme works fine!

Let me try with that epub and I let you know!

If I put publisherStyles to false then I get a glitch which change the page but it doesn't do any change to the font. I've already tried with this because I read it in another Q&A but as I mentioned before, this generates a glitch

That was the reason to write you because I though that I was missing something

[mickael-menu]

Are you able to change the font size of this book when running the Test App? If not, could you share this book with me? Privately if needed

[pattyzamsal]

Hello @mickael-menu

I tested with your EPUB, and the code works fine to increase/decrease the font.

Then, I tried to increase/decrease the font of this specific EPUB using the Test App and I couldn't! Nothing happened.

Sorry for answering you late, I was waiting to get a permission to send you the epub. Can I send it to you by email? Could you give me your email, please?

[mickael-menu]

You can find my email on my GitHub profile: https://github.com/mickael-menu