This commit fixes graphics rendering when more than one OS window is
open, all OS windows are semi-transparent, and multiple windows contain
graphics.
This commit closes#2310.
`glfwGetCocoaKeyEquivalent()` in `glfw/cocoa_window.m` expects the returned characters to be of type `unichar`, which won't work for all unicode characters because it is defined as `unsigned short` according to https://developer.apple.com/documentation/foundation/unichar?language=objc, which is only guaranteed to be at least 16 bits in size. The code calling this function also expects the encoding to be UTF-16.
When I added the various keys in https://github.com/kovidgoyal/kitty/pull/1928, I missed these facts. This means, that `glfwGetCocoaKeyEquivalent()` will behave unexpectedly when called with any of the new-ish keys. Luckily this function is currently only used for determining the macOS shortcut for `new_os_window` but I plan on using it more in the future.
Some of the constants, e.g. `NSBackspaceCharacter` are UTF-16 constants, so we can't just use UTF-8 everywhere.
I fixed the problem by using either UTF-8 characters packed into a `uint32_t` or UTF-16 characters in a `unichar` and then converting them to a UTF-8 encoded char string.
`NSEventModifierFlagNumericPad` isn't guaranteed to fit in a `unichar`, which made this undefined behaviour. It also didn't work. I tried to make it work using `NSEventModifierFlagNumericPad` as a modifier instead, as can be seen in this commit, but couldn't get it to work either because the constants used are native key codes and not unicode characters. Therefore the numpad keys will be removed in the next commit.
The time is stored in a signed 64 bit integer with nanosecond accuracy. This eliminates the possibility of floating-point inaccuracies.
`monotonic_t` can currently hold values large enough to work correctly for more than 200 years into the future.
Using a typedef instead of directly using `int64_t` everywhere will also allow easily changing the datatype in the future should the need arise for more precise or bigger time values.
This matches behavior on macOS. Had initially set the code to process
on every loop tick in an attmept to workaround the issue of the event
loop freezing on X11 until an X event is delivered. However, in light
of #1782 that workaround was incorrect anyway. Better to have similar
behavior across platforms. This also has the advantage of reducing CPU
consumption.
Also add a simple program to test event loop wakeups.
