Swapped keyboard keys not always recognized

[Steven De Herdt]

Minor inconvenience: I have my left ctrl and caps_lock switched, but the current dev version doesn't recognize that when deleting roads or presetting locations. When I got the clue that I have to press the real ctrl for that, I was a bit surprised that text input does honour my peculiar caps_lock key location.
I would guess that it works like this since SDL2 - no more than a guess though. Can WL (reasonably) be made to follow my keyboard settings like it used to?

[GunChleoc (gunchleoc)]

We went for the physical key in some cases:

   if (get_key_state(SDL_SCANCODE_LCTRL) || get_key_state(SDL_SCANCODE_RCTRL))

and for the semantic key in others:

   if (code.mod & (KMOD_LCTRL | KMOD_RCTRL))

I agree that the behavior needs to be consistent, and I vote for the second option.

[Steven De Herdt (stdh)]

This inconvenience became a bit too big for me and I dug around some, with resulting patch attached. In most cases I replaced (get_key_state(SDL_SCANCODE_LCTRL) || get_key_state(SDL_SCANCODE_RCTRL) with (SDL_GetModState() & KMOD_CTRL) [note: KMOD_CTRL==KMOD_LCTRL|KMOD_RCTRL], except in one place where the keysym was available. Direct invocation of the SDL function is perhaps not the cleanest design, it feels strange handling hardware while deciding what flags/buildings to bulldoze. I'm no expert programmer/designer, but some comments (e.g. ui_basic/window.cc line 367, identical comment repeated a few times) seem to agree it's fishy. I suppose doing it cleanly would require some substantial refactoring...

(This patch also removes a bitshift of booleans (in actionconfirm.cc), did that serve any purpose besides being confusing?)

There's some "get_key_state(SDL_SCANCODE_*)" I didn't touch: some involving arrow keys and/or keypad (interactive_base.cc and game_message_menu.cc) and some involving Mac (wlapplication.cc).

I manually tested this patch and it seems to work.

P.S. One trigger for working on this is that "ctrl-+" does not actually zoom in. The SDL wiki says SDLK_PLUS is a virtual key, so we seem to need something else. But "ctrl-shift-=' is maybe not universal (works for Belgian AZERTY though)... Also "ctrl-0" in the editor resets zoom and sets toolsize to 10 at the same time.

P.P.S. This got me curious, how are shortcuts (like 'c' for census) supposed to work for non-Latin keyboard layouts? Do their users just habitually switch to QWERTY for gaming or so?

[GunChleoc (gunchleoc)]

Thanks for the patch - I have created a branch.

The bitshift is a typo - on a German keyboard, when you press < + Alt Gr, you get |. So, this was supposed to be ||.

I will fix the ctrl-0 issue in the attached branch.

Actually, I don't know how the hotkeys work for non-Latin keyboards. It's worth looking into.

[GunChleoc (gunchleoc)]

Merge request is up:

https://code.launchpad.net/~widelands-dev/widelands/bug-1618557-keycode/+merge/311870

[Steven De Herdt (stdh)]

Thanks for getting this in.

About the bitshift: I never thought of C++ as a language so robust that you could mistype an operator and still have it working. :) (Well, at least with the left control key.)

I've been looking a bit into "ctrl-+". As I found out, this just works on a German QWERTZ layout. For other layouts, where you might need shift to produce "+", it's not so easy. If we want to make the keyboard shortcut logic work universally we seem to have three choices:
1. use the 'unicode' field of a keyboard event, which is obsolete in SDL2;
2. use TextInput events;
3. translate the symbol '+' to the right Keycode and Keymod for the current layout ourselves, without support by SDL.
Am I missing any more attractive ways to solve this? Good to know: this problem also occurs for other shortcuts which require shift, like the number keys in AZERTY.

[GunChleoc (gunchleoc)]

Fixed in build20-rc1