by default utilises the color space of the screen on which the window is
located. if a specific value is defined, it will instead be utilised.
depending on the chosen color space the macOS EDR (HDR) support is
activated and that OS's transformation (tone mapping) is used.
Fixes#7341
initially we drew on a dedicated render queue to circumvent certain
bottlenecks on the main queue, like concurrent events that could lead
to late drawing.
though due to the way cocoa works we need to draw an the main queue
otherwise we get undefined behaviour that could lead to crashes.
Fixes#10276
this fixes a crash on quit, when a CATransaction from a system owned
thread/event is happening at the same time. locking the context
synchronises these access and prevents the race condition.
the draw operation induced by any display call from the CAOpenGLLayer
doesn't need that lock, since the display function already does lock
that current context.
Fixes#11681
c784820454 introduced a bool option type
as a replacement for the flag type, but didn't actually transition and
remove the flag type because it would have been too much mundane work.
move all backend independent code parts in their own folder and files,
to simplify adding new backends. the goal is to only extend one class
and add the backend dependent parts there. usually only the (un)init,
config and related parts need to be implemented per backend. furthermore
all needed windowing and related events are propagated and can be
overwritten. the other backend dependent part is usually the surface for
rendering, for example the opengl oder metal layer.
in the best case a new backend can be added with only a few hundred
lines.
der richter