It would be nice for accessibility to have a kwin effect to magnify a window instead of either an area around the mouse cursor or the entire workspace. I would like this effect to scale up the entire window. So a window that is normally 200x100 pixels would take up 400x200 pixels at 200 % magnification. And the content, window decorations and mouse cursor would be bigger as well. Like, instead of having a magnifying area around the mouse cursor the area would be as big as the window and would grow accordingly with the magnification.

Ideally one would be able to apply this effect via window rules. That way I could work around apps with poor accessibility options. Especially old Java programs or games and their launchers.

For maximized and fullscreen windows I guess it should work like the current workspace zoom.