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.
use 4 RMT channels, then I2S#1, then RMT 5-8. This allows to have up to 5 "fast" LED pins.
"Even though the ESP32 has 8 channels of RMT hardware, using beyond 4 has shown to cause sending delays." (https://github.com/Makuna/NeoPixelBus/wiki/ESP32-NeoMethods#rmt)
* make local functions "static"
* use fast_ int types where possible
* use native min/max instead of MIN/MAX macros. Macros evaluate each parameter TWICE!!
* adding __attribute__((pure)) and __attribute((const)) to help the compiler optimize
* ws.cpp: reduce max "live leds" in fastpath mode
