这一篇来研究下LVGL V8下colorwheel色轮的使用，这个色轮是HSV样式的，下面的代码通过创建色轮对象，然后添加对象事件处理，移动旋钮，显示对应的颜色和RGB值

还是通过codeblock来模拟代码的运行，代码如下：

// 事件回调函数
static void colorwheel_event_callback(lv_event_t * event)
{
    if (event == NULL)
    {
        printf("[%s:%d] event is NULL\n", __FUNCTION__, __LINE__);
        return ;
    }

    lv_event_code_t code = lv_event_get_code(event);
    if (code == LV_EVENT_VALUE_CHANGED)
    {
        lv_obj_t *obj_colorwheel = lv_event_get_current_target(event);
        lv_obj_t *obj_label = lv_event_get_user_data(event);
        if (obj_label != NULL && obj_colorwheel != NULL)
        {
            lv_color_t color = lv_colorwheel_get_rgb(obj_colorwheel);
            lv_label_set_text_fmt(obj_label, "Red:%d\n\nGreen:%d\n\nBlue:%d", color.ch.red, color.ch.green, color.ch.blue);
        }
    }
}


/*
创建一个HSV色轮colorwheel对象，沿色轮移动按钮显示对应的RGB值
*/
void lv_colorwheel_test()
{
    lv_obj_t *obj_color_label = lv_label_create(lv_scr_act());
    if (obj_color_label == NULL)
    {
        return ;
    }

    //lv_label_set_text(obj_color_label, "");
    lv_obj_align(obj_color_label, LV_ALIGN_LEFT_MID, 100, 0);

    lv_obj_t * obj_colorwheel = lv_colorwheel_create(lv_scr_act(), true);
    if (obj_colorwheel != NULL)
    {
        //lv_obj_center(obj_colorwheel);
        lv_obj_set_size(obj_colorwheel, 200, 200);
        lv_obj_align(obj_colorwheel, LV_ALIGN_RIGHT_MID, -100, 0);
        // 处理值改变事件LV_EVENT_VALUE_CHANGED
        lv_obj_add_event_cb(obj_colorwheel, colorwheel_event_callback, LV_EVENT_VALUE_CHANGED, (void *)obj_color_label);

        lv_color_t color = lv_colorwheel_get_rgb(obj_colorwheel);
        lv_label_set_text_fmt(obj_color_label, "Red:%d\n\nGreen:%d\n\nBlue:%d", color.ch.red, color.ch.green, color.ch.blue);
    }
}

运行效果：

参考文献：LVGL『Color picker颜色选择器控件』介绍