Comment 4 for bug 1649736

The "broken widget rendering" is a manifestation of how GTK3 handles HiDPI. GTK3 doesn't natively scale at 1/8 increments, so Unity's scaling is working around that by messing with the size of text and widgets.

To give you an idea, I'm attaching a screenshot of the same window as rendered at 1x (as on a 140dpi screen) and 1.5x (as on a 210dpi screen). You can see how the text nearly overflows the switches and drop downs. Plus the window doesn't resize correctly (same width in pixels but physically smaller).

To actually get non-integer scaling to look right would be quite a big effort. We'd need to either patch the major toolkits to support non-integer scaling or modify Ubuntu's window manager/compositor to render individual windows at the next integer scale up (2x) and then rescale the window down to the correct size (1.5x), plus add proper input redirection support in X.

That's why I'm suggesting we minimize the number of people we give non-integer scaling.