lv_disp_drv_t disp_drv;               /*Descriptor of a display driver*/
lv_disp_drv_init(&disp_drv);          /*Basic initialization*/
disp_drv.disp_flush = disp_flush;     /*Set your driver function*/
lv_disp_drv_register(&disp_drv);      /*Finally register the driver*/
    
void disp_flush(int32_t x1, int32_t y1, int32_t x2, int32_t y2, const lv_color_t * color_p)
{
    int32_t x, y;
    for(y = y1; y <= y2; y++) {
        for(x = x1; x <= x2; x++) {
            sep_pixel(x, y, *color_p);  /* Put a pixel to the display.*/
            color_p++;
        }
    }

    lv_flush_ready();                  /* Tell you are ready with the flushing*/
}
    

lv_indev_drv_init(&indev_drv);             /*Descriptor of a input device driver*/
indev_drv.type = LV_INDEV_TYPE_POINTER;    /*Touch pad is a pointer-like device*/
indev_drv.read = touchpad_read;            /*Set your driver function*/
lv_indev_drv_register(&indev_drv);         /*Finally register the driver*/

bool touchpad_read(lv_indev_data_t * data)
{
    static lv_coord_t last_x = 0;
    static lv_coord_t last_y = 0;

    /*Save the state and save the pressed coordinate*/
    data->state = touchpad_is_pressed() ? LV_INDEV_STATE_PR : LV_INDEV_STATE_REL; 
    if(data->state == LV_INDEV_STATE_PR) touchpad_get_xy(&last_x, &last_y);
   
    /*Set the coordinates (if released use the last pressed coordinates)*/
    data->point.x = last_x;
    data->point.y = last_y;

    return false; /*Return `false` because we are not buffering and no more data to read*/
}

lv_obj_t * btn = lv_btn_create(lv_scr_act(), NULL);     /*Add a button the current screen*/
lv_obj_set_pos(btn, 10, 10);                            /*Set its position*/
lv_obj_set_size(btn, 100, 50);                          /*Set its size*/

lv_btn_set_action(btn, LV_BTN_ACTION_CLICK, btn_action);/*Assign a callback to the button*/
lv_obj_t * label = lv_label_create(btn, NULL);          /*Add a label to the button*/
lv_label_set_text(label, "Button");                     /*Set the labels text*/

lv_res_t btn_action(lv_obj_t * btn)
{
    printf("Clicked\n");
    return LV_RES_OK;
}

static lv_style_t style_btn_rel;                        /*A variable to store the released style*/
lv_style_copy(&style_btn_rel, &lv_style_plain);         /*Initialize from a built-in style*/
style_btn_rel.body.border.color = LV_COLOR_HEX3(0x269);
style_btn_rel.body.border.width = 1;
style_btn_rel.body.main_color = LV_COLOR_HEX3(0xADF);
style_btn_rel.body.grad_color = LV_COLOR_HEX3(0x46B);
style_btn_rel.body.shadow.width = 4;
style_btn_rel.body.shadow.type = LV_SHADOW_BOTTOM;
style_btn_rel.body.radius = LV_RADIUS_CIRCLE;
style_btn_rel.text.color = LV_COLOR_HEX3(0xDEF);

static lv_style_t style_btn_pr;                         /*A variable to store the pressed style*/
lv_style_copy(&style_btn_pr, &style_btn_rel);           /*Initialize from the released style*/
style_btn_pr.body.border.color = LV_COLOR_HEX3(0x46B);
style_btn_pr.body.main_color = LV_COLOR_HEX3(0x8BD);
style_btn_pr.body.grad_color = LV_COLOR_HEX3(0x24A);
style_btn_pr.body.shadow.width = 2;
style_btn_pr.text.color = LV_COLOR_HEX3(0xBCD);

lv_btn_set_style(btn, LV_BTN_STYLE_REL, &style_btn_rel);    /*Set the button's released style*/
lv_btn_set_style(btn, LV_BTN_STYLE_PR, &style_btn_pr);      /*Set the button's pressed style*/

/*Add some effects when the button is clicked*/
lv_btn_set_ink_in_time(btn, 300);
lv_btn_set_ink_wait_time(btn, 100);
lv_btn_set_ink_out_time(btn, 300);