ESP32-HUB75-MatrixPanel-DMA/doc/BuildOptions.md

Build Options and flags

This library supports build-time defines to modify its features or enable greater debugging information. Please use the debugging capabilities before raising any issues.

For example build flags could be set using PlatformIO's .ini file like this

[env]
framework = arduino
platform = espressif32
lib_deps =
    ESP32 HUB75 LED MATRIX PANEL DMA Display
build_flags =
    -DCORE_DEBUG_LEVEL=3
    -DNO_GFX=1
    (etc.....)

Build flags

Flag	Description	Note
CORE_DEBUG_LEVEL	Adjust the espressif ESP32 IDF debug level, for which this library leverages to output information on what is going on when allocating memory etc. This will provide detailed information about memory allocations, DMA descriptors setup and color depth BCM	Set value to at least 3 (Info)
USE_GFX_ROOT	Use lightweight version of AdafuitGFX, without Adafruit BusIO extensions	You must install Adafruit_GFX_Lite library instead of original AdafruitGFX
NO_GFX	Build without AdafuitGFX API, only native methods supported based on manipulating DMA buffer. I.e. no methods of drawing circles/shapes, typing text or using fonts!!! This might save some resources for applications using it's own internal graphics buffer or working solely with per-pixel manipulation.	Use this if you rely on FastLED, Neomatrix or any other API. For example Aurora effects can work fine w/o AdafruitGFX.
NO_FAST_FUNCTIONS	Do not build auxiliary speed-optimized functions. Those are used to speed-up operations like drawing straight lines or rectangles. Otherwise lines/shapes are drawn using drawPixel() method. The trade-off for speed is RAM/code-size, take it or leave it ;)	If you are not using AdafruitGFX than you probably do not need this either
NO_CIE1931	Do not use LED brightness compensation described in CIE 1931. Normally library would adjust every pixel's RGB888 so that luminance (or brightness control) for the corresponding LED's would appear 'linear' to the human's eye. I.e. a white dot with rgb(128,128,128) would seem to be at 50% brightness between rgb(0,0,0) and rgb(255,255,255). Normally you would like to keep this enabled by default. Not only it makes brightness control "linear", it also makes colors more vivid, otherwise it looks brighter but 'bleached'.	You might want to turn it off in some special cases like: Using some other overlay lib for intermediate calculations that makes it's own compensation, like FastLED's dimming functions. running at low color depth's - it might (or might not) look better in shadows, darker gradients w/o compensation, try it you run for as bright output as possible, no matter what (make sure you have proper powering) you run for speed/save resources at all costs
FORCE_COLOUR_DEPTH	In some cases the library may reduce colour fidelity to increase the refresh rate (i.e. reduce visible flicker). This is most likely to occur with a large chain of panels. However, if you want to force pure 24bpp colour, at the expense of likely noticeable flicker, then set this defined.	Not required in 99% of cases.

Build-time variables

Flag	Description	Note
PIXEL_COLOR_DEPTH_BITS=8	Color depth per color per pixel in range 2-8. More bit's - more natural color. But on the other hand every additional bit: eats ~2.5 bits of DMA memory per pixel reduces matrix refresh rate in power of two due to nature of BCM	For large chains of panels (i.e. 6 x 64x64 panels) you WILL need to reduce the colour depth, or likely run out of memory. Default is 8 bits per colour per pixel, i.e. TrueColor 24 bit RGB. For higher resolutions, from 64x64 and above it is not possible to provide full 24 bits colour without significant flickering OR reducing dynamic range in shadows. In that case using 5-6 bits at high res make very small difference to the human’s eye actually. Refer to the I2S memcalc for more details.