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
I've found a code spellchecker, so this is what can be corrected easily. Changes are only affecting comments, readme and a few user-visible strings. So no functional impact expected.
* adding an optional parameter to setBrightness(). ApplyPostAdjustments() will only be called if `immediate=true`. Only ABL will use immediate=true, to ensure electrical safety of equipment.
This allows some optimizations of performance, as ApplyPostAdjustments() is time consuming.
* busses.setBrightness(bri) --> applied to all future pixels (fast, lossless)
* busses.setBrightness(bri, true) --> applied directly to all previously set pixels (slower, lossy)
* getpixelcolor: attribute pure - it reads memory, but does not write
* some optimizations for SEGMENT.blur() and SEGMENT.fadeToBlackBy()
* FX.c:pp remove double calls to blur() and fade_out()
* FX.cpp: SEGMENT.setUpLeds() added to effects, to enable LED buffering (safe some time because getPixelColor does not need to access NeopixelBus)
* a few other optimizations to safe time and avoid "expensive" operations
* set I2C bus speed to 400kHz (default is 100Khz)
* a few other small optimizations and tweaks
* pio: esp32 V4 builds use "patch5" toolchain version, which contains a few bugfixes especially for memory management.
