Add testing of a "true" variant font

[freakboy3742]

What is the problem or limitation you are having?

As noted in #2159, the Endor font doesn't contain a "true" bold or italic, resulting in rendering on iOS and macOS that looks

This contrasts with GTK and Windows, which apply "fake" bold and italic:

Describe the solution you'd like

• Add to the fonts example app an example of a "true" variant font. Recursive has been suggested as a candidate.
• Add a tests to the testbed canvas test that performs an automated test of what the fonts example is rendering. Add one test for each font (i.e. render an image that renders text as normal, bold, italic and bold-italic for each font).

Describe alternatives you've considered

Don't explicitly test variant fonts.

Additional context

No response

[javedarham2-coder]

Hi!
I'd like to work on this issue. I'll start by understanding the existing font example and test setup, then work on adding support for testing a true variant font as described.

I'll start investigating it and submit a PR once I have a solution.

[harshitnagar22]

Opened a PR for this: #4574

Added Recursive variable font to the fonts example app with all 4 variants, plus a canvas test covering Endor, Roboto, and Recursive in normal, bold, italic, and bold-italic.

[javedarham2-coder]

Hi! @harshitnagar22

I just noticed that you've already opened a PR for this issue. Unfortunately, I had also started working on it and spent quite a bit of time understanding the codebase before discovering your PR.
It would really help future contributors if you could leave a quick comment on the issue when you start working on it .
That helps avoid duplicate effort and saves others from spending time on the same implementation.
Thanks, and good luck with your PR!

[harshitnagar22]

Hey @javedarham2-coder — ah, really sorry about that. Should've commented on the issue first, my bad. Appreciate you being cool about it and sorry you spent time on it too. Thanks!