Is DPI really a term in the iOS community? I thought DPI was a holdover from the print-era, and the politically-correct term was PPI (pixels-per-inch - not "physical" pixels per inch).
I've heard 1x pixels called "device-independent pixels", "CSS pixels", and "points"; but I've never seriously heard the term "device-pixels-per-inch" until this article.
I don't mind people using the term DPI. The part that confused me is that the OP is drawing a distinction between them.
In my mind DPI == "dots per inch", PPI == "pixels per inch", and they measure the same thing (although some people frown upon using DPI in a digital context). The author redefines them to mean "device pixels per inch" and "physical pixels per inch", where PPI / devicePixelRatio == DPI. I wasn't sure if that's an OP-thing or an iOS thing.
I've heard 1x pixels called "device-independent pixels", "CSS pixels", and "points"; but I've never seriously heard the term "device-pixels-per-inch" until this article.