Described in more detail in the upstream MR*. mpv naively rounds which makes us susceptible to the mentioned error. Fix this by keeping wl->scaling and wl->pending_scaling in the base 120 units. Use the simple rounding algorithm when needed for calculating widths/heights. Create a wl->scaling_factor as convenient shorthand for scale / 120 which is what wl->scaling used to previously be. *: https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/309