Fix rotated views on HiDPI outputs
Test plan: set output scale to 2, open gnome-calculator
, rotate it, check that pointer events work (clicking on buttons, text inputs...). Check that views are rendered at the correct position (open menus), except the combobox. The combobox uses a popup and these don't work anymore on non-HiDPI outputs (hence, this is an unrelated regression, #415 (closed)).
Fixes #402 (closed)