Yeah, well, what Gnome does is if you ask it for 150% scaling, then it actually gives you 147% scaling or 152% scaling to make the number come out even.
Don't know about how Gnome does that[1], but Apple certainly does that, and it allows them to limit compounding of the pixel errors to a group of 8 or 9 pixels. Each new pixel group starts without any compounded error.
[1] Last time I checked, they didn't scale entire framebuffer as Apple does it, with output scaler. It looked like they were scaling surfaces individually with GPU and then composed the scaled surfaces into framebuffer with the same dimensions as the display resolution.
