Module drivers

Logic for interoperability with the lv_drivers project.

This dummy module hosts the documentation for using the reexported macros, which are namespaced under LVGL. The appropriate drivers must be enabled in lv_drv_conf.h, or compilation will error.

The sdl example shows how to use both input and display drivers to port the button_click example.

Building

To compile in support for drivers, ensure the drivers feature is enabled (this feature is enabled by default). Also ensure that the C configuration for the drivers is located at the same path as the configuration for LVGL itsel (i.e. the directory pointed to by DEP_LV_CONFIG_PATH contains both lv_conf.h and lv_drv_conf.h).

Depending on desired drivers, certain environment variables need to be set. LVGL_INCLUDE lists directories to be searched for headers during compilation, and LVGL_LINK lists libraries that will be linked in. By default, LVGL_INCLUDE is set to /usr/include,/usr/local/include and LVGL_LINK is set to SDL2. Automatically detecting necessary libraries based on enabled features is on the roadmap but not yet implemented.

Display drivers

A display driver can be instantiated based on a buffer and output dimensions. The initialization macro will also perform any logic necessary to initialize its respective display, and register it with LVGL.

Note: Some drivers, such as the GTK driver, are broken in upstream lv_drivers. Check open issues upstream if you encounter errors.

use lvgl::DrawBuffer;
use lvgl::lv_drv_disp_sdl;

const HOR_RES: u32 = 240;
const VER_RES: u32 = 240;

let buffer = DrawBuffer::<{ (HOR_RES * VER_RES / 2) as usize }>::default();
let display = lv_drv_disp_sdl!(buffer, HOR_RES, VER_RES).unwrap();
// ...

Input drivers

Input drivers can immediately be instantiated with no parameters. Similar to display drivers, initialization logic and registration with LVGL is performed automatically on macro invocation. Setting a custom feedback_cb is not (yet) supported, but can be done unsafely with raw C FFI calls.

Note: The InputDevice trait must be in scope at macro invocation.

use lvgl::input_device::InputDriver;
use lvgl::lv_drv_input_pointer_sdl;

fn main() {
    // IMPORTANT: Initialize a display driver first!
    // ...
    let _input = lv_drv_input_pointer_sdl!(display);
    // ...
}