Comment 38 for bug 1500282

Thanks a lot for your elaborate responses.

So with that GTK change and that Xorg change that was referenced earlier, actually the only way to tell applications to scale will be the Xft.dpi/text-scaling-factor setting.

Some more questions came to mind:
 - Android doesn't seem to have a blur problem, and I imagine there is no stepped scaling there?
 - Windows 10 introduced monitor-specific DPI scaling, I'm not sure if these are stepped or not, but it seems that it really reads the DPI from EDID.
 - Web developers who care about multi-device support know that they *will* be scaled to arbitrary factors (especially on mobile devices) and will use vector graphics to avoid blur. Obviously that only works for vectorizable graphics that they control, but I would guess that at least 90% of the rasterized non-vectorizable images on the web are photographs and thus not pixel-critical.