[gemkeyboard] keycodes

[60-hz]

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Gemwin keycode reports through [gemkeyboard] are working only in Capital letters.
Also, non english keyboard is not taken into account (testing with french keyboard layout).

[umlaeute]

what's worse is that the keycodes are highly dependent on the actual windowing backend.

here's a test with a german keyboard layout:

windowing backend	key combination	normal printout	gemkeyboard
glfw3	A	a	65
glfw3	Shift_L+A	A	340 65
glfw3	Ö	ö	59
glfw3	Shift_R+Ö	Ö	344 59
glut	A	a	97
glut	Shift_L+A	A	112 65
glut	Ö	ö	246
glut	Shift_R+Ö	Ö	113 214
glx	A	a	38
glx	Shift_L+A	A	50 38
glx	Ö	ö	47
glx	Shift_R+Ö	Ö	62 47
sdl	A	a	38
sdl	Shift_L+A	A	50 38
sdl	Ö	ö	47
sdl	Shift_R+Ö	Ö	62 47
sdl2	A	a	4
sdl2	Shift_L+A	A	225 4
sdl2	Ö	ö	51
sdl2	Shift_R+Ö	Ö	229 51

as you can see

• some backends will include capitalisation (glut), while others will not (glfw3, glx, sdl, sdl2`)
• some backends will use unicode points (glut at least for the printable characters, but notably not for Shift), others will almost use ASCII (glfw3 where it works for A but not for Ö), some will use XKeyCodes (glx, sdl) and some will use their own (sdl2)

traditionally i've always been torn between exposing low-level functionality and normalizing the output so it is consistent across all windowing backends and platforms.
in practice, normalizing the output is a task that i have no hope of implementing.

the important takeaway is, that you should not consider the output of [gemkeyboard] to be an ASCII value (or unicode point).
it's a number that represents a given key, not a letter.

[umlaeute]

see also #15