When I use regular or fractional scaling, content generated by Wine does not scale. This looks particularly bad under fractional scaling because the Wine content takes up relatively less of the screen.
No scaling, 125% scaling, 200% scaling. Adjusted for perceived height.
In other software that does not honor desktop scaling I have found an independent scaling setting for that software. (e.g. layout.css.devPixelsperPx in Firefox).
How can I set scaling in Wine?
To set scaling in Wine you need to adjust the Wine DPI setting. You can find this is Wine Configuration (winecfg) under the Graphics tab. In this example under 125% fractional desktop scaling, setting the Wine screen resolution to 240dpi scales Wine content appropriately (for my tastes).
You will need to configure this setting for each wineprefix.
If you need to scale an individual application (like a game) then you'll need to do it from X. Wine's dpi setting only changes the font size, which makes the window size increase, but it doesn't actually scale anything.
I found the answer here using xpra and run_scaled:
