X11 supports fractional DPI just fine, and Android, Windows, and even the web handle it fine. If I zoom to 150% on a website, how wide will a 1px line be? PDF

X11 supports fractional DPI just fine, and Android, Windows, and even the web handle it fine. If I zoom to 150% on a website, how wide will a 1px line be? PDF handles that fine, the web handles it fine, Android handles it fine. It's only in recent years that suddenly this has become an issue that "can't" be solved. I honestly don't care if regular desktop apps waste performance, as long as Qt, Android, Electron, games etc are just rendered at the fractional resolution properly.