Emoji That Use Zero Width Joiner Sequences Render Incorrectly

[DuaneOBrien]

Thank you for this awesome tool!

I have discovered what appears to be a bug somewhere in the decktape workflow that is causing incorrect rendering of emoji using ZWJ sequences.

(Background on ZWJ sequences: http://blog.unicode.org/2016/11/113-new-unicode-emoji-plus-skin-tones.html, cf. https://blog.emojipedia.org/emoji-zwj-sequences-three-letters-many-possibilities/)

In summary, decktape renders these characters fine: 📸 📹 📰 📬 🐦

This is because they are single unicode characters.

But decktape renders these characters incorrectly: 🧙‍♂️ 🧛‍♂️ 🤹‍♂️ 🧟‍♂️ 🧜🏻‍♂️

This is because these individual emoji are rendered by joining one or more single unicode characters using a ZWJ.

I've created a demo slidedeck that can be used to verify/troubleshoot: https://duaneobrien.github.io/decktape-emoji-bug/

Sourcecode and the decktape output are in https://github.com/DuaneOBrien/decktape-emoji-bug

This may ultimately be a Puppeteer bug, but I don't see any issues in either repo (open or closed)

decktape version: 2.9.1 (fresh install today)
Chrome version: 71.0.3578.98 (unsure if Puppeteer uses this or not)

[astefanutti]

Thanks a lot for the feedback and the awesome bug report! I'll investigate ASAP.

[astefanutti]

I've just tested with a newer version of Puppeteer (1.12.2) and that fixes the issue. That version comes with Chromium 73, as opposed to Chromium 71 for the current version used by Decktape.

I usually wait for the newer Chromium version to land in Alpine as it used in the Docker image. I did some quick tests and it seems Puppeteer is compatible with older Chromium version (i.e. 71), so if that's urgent for you, I could do the upgrade and that would fix the issue for the NPM install.

I realise another thing would be to add some Emoji font packages to the Docker image, like font-noto-emoji.

[DuaneOBrien]

The issue isn’t urgent by any stretch, it’s just a few wonky emoji in a slide deck. It sounds like we just need to wait a few weeks for the new Chromium to drop?

[astefanutti]

Cool. Yes, it can take a couple of weeks.

[astefanutti]

For reference, an interesting discussion on how to enable Noto Coloraturas Emoji on Linux googlefonts/noto-emoji#36 that may help for the Docker image.

[astefanutti]

It should be fixed in version 2.9.2. Thanks for your patience.

[DuaneOBrien]

Verified fixed, thanks for your help!