With a background in linguistics and a descent understanding of Unicode, I thought I had something of a grip on the complexities of text. But then I read Text rendering hates you[0] and realized I had no idea how hard rendering text really is. The most striking example for me is the Arabic example where allh (Allah) is styled with different colours on each of the four characters, because this particular character sequence is a mandatory ligature if memory serves, and how do you figure out the colour changes when you're layout out a single glyph from the font?

0: https://faultlore.com/blah/text-hates-you/