Hi! I'm the person who wrote that blog post. If you have any questions whatsoever, please let me know! English is not my native language and "The solution is trivial" was meant sarcastic. The solution isn't trivial at all, nor is it complete, because solving the corner cases is complex. I'd also like to mention ahead of time that DirectWrite/Direct2D is very fast at drawing western (Latin) text without coloring (>200…
I think it's really difficult to convey sarcasm well in text, and what seems obvious to you as a writer might not come across as sarcasm to readers. I certainly didn't understand that as sarcastic right away.
It might be better to address it directly and in a friendly way, like this:
> Like I did, you might be wondering right now why we don't just create our own, much larger lookup table and wrap it around Direct2D. Well, we can’t just tell Direct2D to use our custom cache [...]