very minor changes:
* HUB75 bus don't leave _len uninitialized, handle display == nullptr before using display members
* __attribute__((pure)) was in the wrong location
* wled00.ino: made lps (loops-per-second) calculation a bit more accurate
similar to getPixelColor, but returns the original pixel without brightness adjustments.
* getPixelColorRestored is used by segment::sPC and segment::gPC
* getPixelColor is still used by ABL (auto brightness limiter)
`mxconfig.clkphase = false;` seems to help reduce flicker on some panels.
@netmindz I think we should add a checkbox to the UI - something like "clocked on positive edge" (default = checked) which means clkphase = true. when unchecked, we set clkphase = false.
the HUB75 driver seems to randomly produce glitches, especially on hight contrast edges.
* roll back to HUB75 version 3.0.10 (known good)
* limit max brightness to 238 (=92%)
* add short delay after starting the driver
* code cleanup, removing some unneeded sanity checks
* use dirty bits in double buffer mode, too -> only not-black pixels are drawn into the back-buffer (20%-30% faster)
Instead of using the memory-hungry driver double buffer, this implements a LEDS buffer inside the BusHub75Matrix class.
--> up to 50% faster
--> uses one "dirty" bit per pixel, to only re-transmit pixels that changed after the last "show"
* move HUB75 implementation into bus_manager.cpp
* add "override" keyword
* include FastLED.h if not included previously
* move RGB macros into bus_manager.h
adding hints for the compiler for optimization.
In case your custom build complains about "const", just remove the keyword. based on e82f38e277, but going further :-)
* "const" class functions : function does not modify any class attributes ( --> "this" becomes const)
* __attribute__((pure)) : function return value depends only on the parameters and/or global variables. The function does not modify any global or static variables.
* __attribute__((const)) : function only examines arguments (no globals), and has no effects except the return value. This slightly more strict than "pure"
* hot: tells the compiler "this functions is called very often"
* cold: the opposite of hot
