Moving text width measure to it's own function, with cache

[ElNounch]

No description provided.

[espadrine]

Thanks for contributing!

Do you have benchmark figures that justify the cost of RAM?

As an aside, all of the RAM of our current Heroku instances is currently allocated, so we'll have to wait for us to move to new servers to merge this.

[AdrieanKhisbe]

now we are not on heroku I think we can merge it :)

[espadrine]

I'd like to further compare this to what #496 gives, performance-wise, both to determine if it would have any impact on performance (whether positive or negative), and to see if a switch to pdfkit doesn't simply kill that bird too with one stone. Going from a median of 70ms to one of 20ms may give way better results than this patch, which will only speed up 256 strings.

(All performance-related patches take quite a bit of time to process, as they often require benchmarks and tweaks.)

[olivierlacan]

There's no feedback from @ElNounch in nearly two years. I'm going to close this and @espadrine can re-open it if #496 didn't provide the benefits this offers.