TreeMenu

A small hierarchical menu renderer on top of LVGL.

Data model: a static const tree of TreeMenuNode. A node is either a leaf (on_activate set, children NULL) or a branch (children set, on_activate ignored). Every non-root level automatically gets a "back" row injected at position 0 — you never declare it yourself.

Input-agnostic: this library never reads any button/input device. The host app wires its own input (physical buttons, touch, ...) to treemenu_next()/treemenu_prev()/treemenu_activate().

Usage

#include <TreeMenu.h>

static void onWifiSelected(const TreeMenuNode *self, void *userdata) {
    // ...
}

static const TreeMenuNode settingsMenu[] = {
    {"Wifi", onWifiSelected, NULL, 0},
};

static const TreeMenuNode rootMenu[] = {
    {"Settings", NULL, settingsMenu, 1},
};

void setup() {
    // ... after the LVGL display driver is registered ...
    TreeMenuConfig cfg = {0};
    cfg.parent          = lv_scr_act();
    cfg.row_height       = 18;
    cfg.color_active     = 0x2266ff;
    cfg.color_text       = 0xffffff;
    cfg.color_text_active = 0xffffff;
    cfg.color_separator  = 0x333333;
    cfg.color_chevron    = 0xffffff;
    cfg.bg_color         = 0x000000;
    treemenu_init(&cfg, rootMenu, 1);
}

// Wire your own buttons/touch to these:
//   treemenu_next();      // move selection down, wraps around
//   treemenu_prev();      // move selection up, wraps around
//   treemenu_activate();  // enter a branch / back out / fire a leaf's on_activate

See src/TreeMenu.h for the full TreeMenuConfig (colors, sizing, an optional breadcrumb strip, ...).

Testing

TreeMenu is pure C on top of LVGL — no hardware, no Arduino dependency — so its tests run entirely on the host against a real (headless) LVGL instance (a dummy display driver, no actual rendering):

pio test -e native

CI runs this on every push/PR — see .github/workflows/tests.yml.

Project structure

src/TreeMenu.h/.c            Public API + implementation
test/test_native/            Unit tests, run on the host against headless LVGL

License

MIT