Allow disabling ligatures in Text

[naveen521kk]

List of Changes

• Allow users to disable ligatures and also fix Code with it.
• Revert make Paragraph use CairoText #798
• number of submobjects = number of chars if ligaratures are disabled.

Explanation for Changes

Better than using CairoText.

Testing Status

Acknowledgement

• I have read the Contributing Guidelines

[PgBiel]

typo

[leotrs]

After a provisional skimming, this looks good in general. I have to take a closer look. Could you please add a couple of tests?

[behackl]

This looks good to me, I also seem to be able to use a monospace font without problems:

Testing Code is a bit tedious as long as we are not able to pass code directly, but have to read a corresponding file. I'd be okay with delegating adding tests to a later point in time where the interface of Code has been refactored a bit.

I'm on the fence whether we should use the current implementation using CairoText for the release, or whether we should get this in before. I probably have a slight preference for merging it after the release.

[naveen521kk]

I will only see a simple problem with this. This will not allow passing something like Arabic, or Hindi or some font which heavily depends on ligatures, from within the code and will look worse. This could be a fix for a short time but this definitely needs to be refactored so that Pango takes the responsibility of colouring it (which it does) instead of manipulating the arrays. But this can't be done for now as our SVG parser ignore style element without which it is not possible. One way it can be fixed is to make it not inherit from SVGMobject instead inherit directly from VMobject and provide methods for working directly with Pango which definitely requires a lot of work though. Also, the present bindings don't support Pango.Attributes without which this can't be done. So, that would require pangocffi to support that.

[leotrs]

This will not allow passing something like Arabic, or Hindi or some font which heavily depends on ligatures, from within the code and will look worse.

This is why I'm fine with using this fix for CodeMobject, but not for Text itself. I agree this should only be a temporary fix.

Point taken on the tests.

Given the absence of tests, I vote we merge this right after the release.

[naveen521kk]

Ready for review.

[leotrs]

@naveen521kk could you please solve the merge conflict? 🙂

[naveen521kk]

I didn't expect this lol. Will do no worries 😊

[naveen521kk]

@leotrs done. Also, typed(python typing) a few things.

[PgBiel]

nice job