Display libraries¶

DISPLAY_CLASS · OLED · E-INK · TFT · ABSTRACTION

MeshCore knows eleven values for DISPLAY_CLASS, from an OLED a couple of centimetres across to an e-ink panel and a colour TFT. Almost none of that shows in the firmware: all displays sit behind a single interface, and which library actually gets compiled in is decided by one build flag per variant. That flag carries a class name rather than an on/off value — one of the four configuration mechanisms from ../library-configuration.md.

[!NOTE] Source. This page was verified against the firmware itself: MeshCore v1.16.0, commit 03b6ef4, 28 July 2026 — files platformio.ini, the seventy-nine variants/*/platformio.ini, src/helpers/ui/DisplayDriver.h, src/helpers/ui/SSD1306Display.h and examples/simple_repeater/main.cpp.

How MeshCore calls this group¶

The abstraction is called DisplayDriver. Every display driver inherits from it and implements the same methods:

src/helpers/ui/DisplayDriver.h r.6-24

class DisplayDriver {
  int _w, _h;
protected:
  DisplayDriver(int w, int h) { _w = w; _h = h; }
public:
  enum Color { DARK=0, LIGHT, RED, GREEN, BLUE, YELLOW, ORANGE }; // on b/w screen, colors will be !=0 synonym of light

  int width() const { return _w; }
  int height() const { return _h; }

  virtual bool isOn() = 0;
  virtual bool isEink() { return false; } // default to non-eink, override in eink drivers
  virtual void turnOn() = 0;
  virtual void turnOff() = 0;
  virtual void clear() = 0;
  virtual void startFrame(Color bkg = DARK) = 0;

Which implementation it becomes is stated by the variant with -D DISPLAY_CLASS=…. The sketches know only that name:

examples/simple_repeater/main.cpp r.42-46

#ifdef DISPLAY_CLASS
  if (display.begin()) {
    display.startFrame();
    display.setCursor(0, 0);
    display.print("Please wait...");

If DISPLAY_CLASS is not defined, all display code disappears from the build. There is also a NullDisplayDriver for boards that run the UI task but have no screen.

The DISPLAY_CLASS abstraction in MeshCore: every variant picks a display
driver with a single build flag, all drivers inherit from the same
DisplayDriver interface, and behind that sit the individual display libraries
from Adafruit, GxEPD2, U8g2 and LovyanGFX

Adafruit SSD1306¶

The SSD1306 is the controller of the small monochrome OLED panels of 128 × 64 or 128 × 32 pixels found on most MeshCore boards. Adafruit's library talks to it over I²C or SPI and keeps a full framebuffer in RAM. With twenty-three variants this is the most common display library in the repo, and SSD1306Display is by far the most common DISPLAY_CLASS. The driver sets SSD1306_NO_SPLASH before the include, so the Adafruit logo does not appear at start-up.

Adafruit SH110X¶

The SH1106 and SH1107 are OLED controllers that closely resemble the SSD1306 but have a slightly different memory layout — drive a panel with one of these as an SSD1306 and the image comes out shifted by a few pixels. The library supports both types. In seven variants: lilygo_tbeam_1w, lilygo_tbeam_supreme_SX1262, nano_g2_ultra, station_g2, station_g3_esp32, thinknode_m2 and wio-tracker-l1, with SH1106Display as the driver.

zinggjm/GxEPD2¶

GxEPD2 is the standard e-ink library on Arduino: it knows dozens of panel types, each with its own initialisation sequence and refresh behaviour, and offers both full and partial refresh. Five variants use it — lilygo_techo, lilygo_techo_lite, mesh_pocket, thinknode_m1 and thinknode_m5 — through GxEPDDisplay. The sixth e-ink variant, wio-tracker-l1-eink, fetches a fork: https://github.com/SoulOfNoob/GxEPD2.git, with no revision after the URL.

Adafruit GFX Library¶

GFX is not a display driver but the drawing layer underneath: lines, rectangles, text, fonts and bitmaps, all in a framebuffer a driver then writes to the screen. SSD1306, SH110X, ST7735/ST7789 and Adafruit EPD all four need it and declare it in their own depends=. In eight variants it is additionally declared explicitly in lib_deps — see ../dependencies.md, where that is described as deliberate version control across the chain.

Adafruit BusIO¶

BusIO is Adafruit's shared bus access layer: one API for a register on an I²C or SPI device, so the driver libraries do not have to concern themselves with the bus. Nearly every Adafruit library brings it in through depends=. In exactly one variant it is declared explicitly, sensecap_indicator-espnow.

Adafruit ST7735 and ST7789 Library¶

ST7735 and ST7789 are controllers for small colour TFT panels. The library supports both and works on top of GFX. Six variants use it: heltec_t096, heltec_t1, heltec_tracker, heltec_tracker_v2, heltec_v4 and lilygo_tdeck, with ST7735Display, ST7789Display or ST7789LCDDisplay as the driver. This library drags in two libraries named nowhere else — Adafruit seesaw Library and SD — because its examples need them.

Adafruit EPD¶

Adafruit EPD is Adafruit's e-ink library, supporting their own panels and breakouts. It is declared in one variant, mesh_pocket, pinned exactly to 4.6.1. No include of Adafruit_EPD can be found anywhere in the source; that observation is described in ../dependencies.md.

olikraus/U8g2¶

U8g2 is a monochrome graphics library supporting a large number of display controllers, with a font system of its own and the option to work without a full framebuffer — usable on boards with little RAM. One variant uses it, lilygo_techo_card, through U8g2Display.

lovyan03/LovyanGFX¶

LovyanGFX is a graphics library for colour displays that uses DMA on ESP32 and is therefore fast on large panels. One variant uses it, sensecap_indicator-espnow, through LGFXDisplay.

heltec-eink-modules¶

For Heltec's e-ink modules, two different forks of the same library are fetched, both as a zip of a full commit hash:

Fork	Commit	Variants
`Quency-D/heltec-eink-modules`	`563dd41`	`heltec_e213`, `heltec_e290`
`todd-herbert/heltec-eink-modules`	`9207eb6`	`heltec_wireless_paper`

The accompanying drivers are E213Display and E290Display; both include heltec-eink-modules.h and use CRC32 to decide whether the screen needs refreshing at all — see utilities.md.

Overview¶

Library	Version	Variants	Driver
`adafruit/Adafruit SSD1306`	`^2.5.13`	23	`SSD1306Display`
`adafruit/Adafruit SH110X`	`^2.1.13` · `~2.1.13`	7	`SH1106Display`
`adafruit/Adafruit GFX Library`	`^1.12.1`	8	drawing layer
`adafruit/Adafruit BusIO`	`^1.17.2`	1	bus access
`adafruit/Adafruit ST7735 and ST7789 Library`	`^1.11.0`	6	`ST7735Display`, `ST7789Display`, `ST7789LCDDisplay`
`adafruit/Adafruit EPD`	`4.6.1`	1	no include found
`zinggjm/GxEPD2`	`1.6.2`	5	`GxEPDDisplay`
`SoulOfNoob/GxEPD2`	no revision	1	`GxEPDDisplay`
`Quency-D/heltec-eink-modules`	`563dd41`	2	`E213Display`, `E290Display`
`todd-herbert/heltec-eink-modules`	`9207eb6`	1	`E290Display`
`olikraus/U8g2`	`^2.35.19`	1	`U8g2Display`
`lovyan03/LovyanGFX`	`^1.2.7`	1	`LGFXDisplay`

Sources¶

Translated from Dutch by Anthropic Claude