[Plugin] Epub3 E-Reader Plugins for Sigil

[RbnJrg]

Originally Posted by DiapDealer

Is your Arch machine virtual (running on a host OS) or is it a physical machine?

It's a physical machine; Arch Linux is installed in one partition of my hard drive.

Basically, I'm trying to determine what is different between our machines. We've got virtually identical builds of Sigil 1.9.10 on Arch Linux, so video hardware/drivers is about the only thing left that I can think of. The fact that other chrome-based renderers are exhibiting the same behavior lends credence to the notion of there being some issue with chromium/WebEngine and your video card/drivers.

I'm not sure but I think Readium also is based on chromium/WebEngine (at least, it generated a folder named QtWebEngine under /home/username/.local/share/Readium Cloud Reader Lite Demo/) and displays the epub correctly; the same folder is generated by EpubJSReader and both plugins show the ebook as is expected. I'm lending to think that the issue is due to a bug in Bibi but if so, then why nor you nor Kevin was able to reproduce the problem? A mystery.

EDIT: By the way, the Calibre Ebook Viewer, is also based on chromium/WebEngine, and there the epub is displayed correctly (no blank pages). So, if the issue were produced by some interaction between video card/drivers and chromium/WebEngine, Calibre Viewer wouldn't be able to display the epub perfectly.

[KevinH]

FWIW, Readium and Calibre viewer use very different javascript than Bibi. So a bug can easily be tickled in one reader / graphics driver / webengine and not in another.

Are you by chance using a display/desktop/theme with its own widget decorations that could be adding margins after body? Does the problem still exist if you choose other desktop themes?

[RbnJrg]

Originally Posted by KevinH

Are you by chance using a display/desktop/theme with its own widget decorations that could be adding margins after body? Does the problem still exist if you choose other desktop themes?

I'm using Adwaita and in window manager I'm using the default theme, so they are native themes that comes with Arch. And by changing themes, the issue persists.

[KevinH]

Thanks for testing and reporting back. I am again out of ideas. Perhaps DiapDealer can figure out how to recreate it.

[RbnJrg]

Hi Kevin and Diap;

I know that Sigil has a built-in version of MathJax but since MathJax can also display equations written in TeX and that TeX formulas are easier to write than the MathML ones, I added to an epub3 the tex-svg.js script from MathJax to see how well (o not) works. I must say that works everywhere (Sigil, Calibre, Thorium, Foliate, Koodo Reader, NeatReader, etc., etc.) and even works the right click menu of MathJax (for example, open the epub in BibiReader; go to the page where are the TeX formulas; do right click and select "Show Math As > MathML Code" and you'll see the TeX formula translated to MathML) BUT it doesn't work in ADE 4.5x (doesn't matter to me) and in the Readium Sigil plugin (this is indeed important), where the the page with TeX equations can't be load (a curious thing because it works fine in Bibi Reader and EpubJS Reader, the others Sigil plugin). Please, when your time permits, can you check if is a Readium plugin bug?

Many thanks in advance.

PS: I attach an epub with both, MathML and TeX equations; the page with MathML formulas is loaded without issues in Readium, but the page with TeX formulas can not. As you will be able to see, the epub has included the mml-svg.js script. This is not necessary because Sigil can show MathML formulas without the MathJax script but I included it so you can see that Sigil, even when it has its own copy of MathJax, it honors the script because with it, the right click menu is available but when you suppress the .js file, MathML equations still are displayed (because of the MathJax built-in copy) but the right click menu is not working anymore.

[KevinH]

TeX equations are not part of the epub3 spec. The spec talks only about mathml. In fact, the MathJax configuration that Sigil uses actually disables TeX support to minimize the size of the plugin itself. Also the TeX equations requires additiinal html and css support as well as the mathjax fonts. Supporting it in Sigil will not happen as it interferes with click to sync between Preview and CodeView, bloats MathJax, and is not epub3 spec compliant.

As for the Readium Reader plugin, it does not support Mathml at all without additional code to pull it in over the net. My guess is that is what you are running into.


So supporting TeX equations I will leave for other

[RbnJrg]

Originally Posted by KevinH

TeX equations are not part of the epub3 spec. The spec talks only about mathml. In fact, the MathJax configuration that Sigil uses actually disables TeX support to minimize the size of the plugin itself. Also the TeX equations requires additiinal html and css support as well as the mathjax fonts. Supporting it in Sigil will not happen as it interferes with click to sync between Preview and CodeView, bloats MathJax, and is not epub3 spec compliant.

As for the Readium Reader plugin, it does not support Mathml at all without additional code to pull it in over the net. My guess is that is what you are running into.

So supporting TeX equations I will leave for other

Hi Kevin;

I see I didn't explain myself very well.

• Yes, I'm aware that TeX equations are not part of the epub3 protocol. If it were, I wouldn't need a javascript to enable the feature.
  
• I don't need that Sigil supports TeX equations; it's enough that Sigil supports javascript; it's enough that a program or app supports javascript in order to get TeX formulas displayed by mean of MathJax javascript.
  
• TeX equations doesn't need svg fonts anymore (MathJax 3.x.). According to the new version, tex-svg.js includes:
  
  '../startup/init.js';
  './preload.js';
  '../core/core.js';
  '../input/tex/tex.js';
  '../output/svg/svg.js';
  '../output/svg/fonts/tex/tex.js'; // This script replaces the svg fonts in previous version of MathJax
  '../ui/menu/menu.js';
  '../a11y/assistive-mml/assistive-mml.js';
  '../startup/startup.js';
  
  
• TeX formulas are displayed without any other resources than the tex-svg.js script, at least, in all the apps and programs I tested (Sigil, BibiReader, EpubJS Reader, Calibre, Thorium, Foliate, Koodo Reader, NeatReader, Lithium, Reasily, Gitden, PocketBook, Aldiko Next, BookFusion, Infinity Reader, OverDrive, BlueFire Reader and I think that will work in any epub reader with support for javascript).
  
• Readium does accept MathML equations. Open the epub I attached in my previous post, remove the mml-svg.js script, run the Readium plugin and you'll see the plugin accepts MathML. In fact, Thorium, based on Readium, supports MathML.

What do I ask then? What I ask is why Readium is not loading the javascript files. I think is a bug but I can't know it because I don't have the way to trace the script loading in Readium (I don't have an "Inspector" there). If you can trace the script when is loaded by the plugin, I will thank if you can tell me where the error happens. That is what I'm asking (I don't need you do anything with Sigil). But if you can't do that, is ok, no problem.

[KevinH]

I will take a look at your math test epub and the ReadiumReader plugin to see if I can see why that js will not work, hopefully tomorrow afternoon my time when I have some free time.

[RbnJrg]

Originally Posted by KevinH

I will take a look at your math test epub and the ReadiumReader plugin to see if I can see why that js will not work, hopefully tomorrow afternoon my time when I have some free time.

Many thanks for your time!!

[KevinH]

The easiest way to debug this is to edit the ReadiumReader plugin.py file to always return -1 (so that the stderr messages are printed to the PluginRunner main window).

If I do that and try to open your epub in Readium Reader and navigate to the Tex xhtml file, I see this error message:

ERROR: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/epub_content/tmp05wraghf/OEBPS/Misc/mml-svg.js:1: Uncaught TypeError: Cannot read properties of undefined (reading 'loader')

So this means that the 'loader' object is undefined. My guess it is conflicts with the MathJax.js version that is stored inside the ReadiumReader.

But that is just a guess.

[KevinH]

If I remove the mml-svg.js and the associated script tag, the mathml document still works (as you said it uses the internal MathJax.js file that is part of the plugin), then I receive the following error message:

ERROR: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61019: Uncaught TypeError: Cannot read properties of undefined (reading 'Browser')

So the code appears to try reading the 'Browser" object but failing.

[RbnJrg]

Many thanks Kevin. It's very strange; I thinked that could be something linked with the MathJax contextual menu, in conflict with the Readium one. But is not that according to your words. If the issue is only with the plugin, well, it wouldn't be so serious, but I'm afraid of the issue is also present on others programs and apps that employ the Readium engine. Thorium (based on Readium) honors the script and displays without problems TeX equations, but, will be able to say the same regarding others programs based on Readium?
Thanks for your help Kevin and I will post here a solution if I can find anyone.

[KevinH]

I enabled more dumps from the javascript console by editing plugin.py and now I am seeing the following:

INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:60843: EPUB doc iframe LOAD URI:
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:60844: file:///Users/kbhend/Library/Application Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/epub_content/tmp9355e5xb/OEBPS/Text/Section0002.xhtml
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61156: EPUB doc base href:
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61157: file:///Users/kbhend/Library/Application Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/epub_content/tmp9355e5xb/OEBPS/Text/Section0002.xhtml
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61014: MathJax VERSION: undefined // undefined // 3.2.2
ERROR: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61019: Uncaught TypeError: Cannot read properties of undefined (reading 'Browser')

So it appears that it is much different from when the first page was loaded as it shows:


the following:

INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61157: file:///Users/kbhend/Library/Application Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/epub_content/tmp9355e5xb/OEBPS/Text/Section0001.xhtml
ERROR: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/epub_content/tmp9355e5xb/OEBPS/Misc/mml-svg.js:1: Uncaught TypeError: Cannot read properties of undefined (reading 'loader')
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:61014: MathJax VERSION: 2.7.5 // 2.7.5 // 2.7.5
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:50391: ReflowableView content resized ... 550 1371 Section0001.xhtml
INFO: file:///Users/kbhend/Library/Application%20Support/sigil-ebook/sigil/plugins/ReadiumReader/viewer/cloud-reader-lite/scripts/readium-js-viewer_all_LITE.js:50401: ... ignored (identical dimensions).

So the first page is being loaded and viewed by the internal MathJax 2.75 that the Readium Reader plugin comes with.

But the second page fails becuase the MathJax.Hub has no Browser object created at all.

My guess is the mix of MathJax versions is the culprit here.

[KevinH]

My guess is anything based on Readium Cloud Reader Lite will need to use a tex-svg codebase that works with MathJax 2.7.x and not MathJax 3.2.2.

Readium's MathJax.js strips out Tex support to save space and speed up loading and because Tex is not a part of the epub3 spec. Just like Sigil does. Your MathJax 3 based tex-svg.js works in Sigil as Sigil is MathJax 3.2.2 based. I am not sure if any Readium Readers are MathJax 3 based as very few groups have adopted MathJax 3 so far.

[KevinH]

According to Readium, MathJax.js single file version is based on MathJax 2.75 and according to its build script:

https://github.com/readium/MathJax-s...aster/build.js

That MathJax Readium version should already support TeX input (see the Readium comment line)

UPDATE

Edit:

I think I am reading that incorrectly. The first line specifies the use of TeX fonts not the TeX input.

So Readium has no TeX input support.