OpenGL ES Display/Inputs driver

Overview

The OpenGL ES display/input driver offers support for simulating the LVGL display and keyboard/mouse inputs in an desktop window created via GLFW.

It is an alternative to Wayland, XCB, SDL or Qt.

The main purpose for this driver is for testing/debugging the LVGL application in an OpenGL simulation window.

Prerequisites

The OpenGL driver uses GLEW GLFW to access the OpenGL window manager.

Install GLEW and GLFW: sudo apt-get install libglew-dev libglfw3-dev

Configure OpenGL driver

Required linked libraries: -lGL -lGLEW -lglfw
Enable the OpenGL driver support in lv_conf.h, by cmake compiler define or by KConfig
#define LV_USE_OPENGLES 1

Usage

#include "lvgl/lvgl.h"
#include "lvgl/examples/lv_examples.h"
#include "lvgl/demos/lv_demos.h"

int main()
{
    lv_init();

    lv_display_t * disp = lv_glfw_window_create(480, 272);

    lv_indev_t * mouse = lv_glfw_mouse_create();
    lv_indev_set_group(mouse, lv_group_get_default());
    lv_indev_set_display(mouse, disp);

    lv_display_set_default(disp);

    LV_IMAGE_DECLARE(mouse_cursor_icon); /*Declare the image file.*/
    lv_obj_t * cursor_obj;
    cursor_obj = lv_image_create(lv_screen_active());   /*Create an image object for the cursor */
    lv_image_set_src(cursor_obj, &mouse_cursor_icon);   /*Set the image source*/
    lv_indev_set_cursor(mouse, cursor_obj);             /*Connect the image  object to the driver*/

    lv_demo_widgets();

    while (1)
    {
        uint32_t time_till_next = lv_timer_handler();
        lv_delay_ms(time_till_next);
    }

    return 0;
}