Tracking issue: improve Key input

The keyboard input in egui is limited in a couple of ways:

• Lots of keys missing from Event::Key
• We don't report the super/meta modifier key
• We don't report modifier key presses (just their state)
• Physical keys not reported on the eframe web backend
• KeyboardShortcut should ignore shift and alt keys for logical keys (e.g. Ctrl Plus may require pressing shift on some keyboards). See https://github.com/emilk/egui/issues/3626 for more

How can I help?

• Look at the code for egui::Key and follow the instructions there for adding new keys
• Investigate if we can get physical keycode on web

Requested keys

• Numpad
• Volume keys
• Curly brackets: { and }
• CapsLock (https://github.com/emilk/egui/issues/2041)
• Modifier keys

Prioir art

• winit: https://docs.rs/winit/latest/winit/event/struct.KeyEvent.html
• https://github.com/pyfisch/keyboard-types

Relevant issues

• https://github.com/emilk/egui/issues/3636
• https://github.com/emilk/egui/issues/3626
• https://github.com/emilk/egui/issues/3415
• https://github.com/emilk/egui/issues/3372
• https://github.com/emilk/egui/issues/3303
• https://github.com/emilk/egui/issues/3099
• https://github.com/emilk/egui/issues/3094
• https://github.com/emilk/egui/issues/2977
• https://github.com/emilk/egui/issues/2041
• https://github.com/emilk/egui/issues/4081

Physical vs Logical keys

• Partially fixed by https://github.com/emilk/egui/pull/3649 (needs web support, if even possible?)

Consider someone owning a physical QWERTY keyboard:

However, they have remapped it to use Dvorak (perhaps even repainting the text on their keyboard):

If they start hitting Caps Lock and then moving to the left, the keys they will be hitting will be

• physical (qwerty): CapsLock, A, S, D, F, …
• logical (Dvorak): CapsLock, A, O, E, U …

The logical keys makes sense for most keyboard shortcuts - if you say "Press Cmd+S to save" in your UI, the user will be looking for the logical key "S" The physical keys are mostly useful for games, where e.g. te physical WSAD on QWERTY moves a character, no matter what the users keymap is.