Music Player Demo for RT-Thread

LVGL音乐播放器演示示例（RT-Thread定制版）

Overview

The music player demo shows what kind of modern, smartphone-like user interfaces can be created on LVGL. It works the best with display with 480x272 or 272x480 resolution.

如何使用这个Demo

在lv_conf.h中增加宏定义#define LV_USE_DEMO_RTT_MUSIC 1

如果想要自动播放的话，可以增加宏定义#define LV_DEMO_RTT_MUSIC_AUTO_PLAY 1

lv_conf.h文件涉及到本demo的宏定义配置示例：

  /* music player demo */
  #include <rtconfig.h>
  #define LV_HOR_RES_MAX          BSP_LCD_WIDTH
  #define LV_VER_RES_MAX          BSP_LCD_HEIGHT
  #define LV_USE_DEMO_RTT_MUSIC       1
  #define LV_DEMO_RTT_MUSIC_AUTO_PLAY 1
  #define LV_FONT_MONTSERRAT_12       1
  #define LV_FONT_MONTSERRAT_16       1

调用lv_demo_music()函数：

static void lvgl_thread(void *parameter)
{
    extern void lv_demo_music(void); //对外声明lv_demo_music()函数
    lv_demo_music(); //调用demo函数运行音乐播放器

    while(1)
    {
        lv_task_handler();
        rt_thread_mdelay(1);
    }
}

参考工程

https://github.com/RT-Thread/rt-thread/tree/master/bsp/qemu-vexpress-a9/drivers/lvgl

注意：这是个模拟器BSP，因此没有board文件夹，LVGL相关配置源文件放在了drivers文件夹中。实际移植时，应当放在BSP目录下的board/ports/lvgl文件夹下。

硬件BSP实际位置参考：https://github.com/RT-Thread/rt-thread/tree/master/bsp/stm32/stm32l475-atk-pandora/board/ports/lvgl

How the spectrum animation works

assets/spectrum.py creates an array of spectrum values from a music. 4 band are created with 33 samples/sec: bass, bass-mid, mid, mid-treble.
The spectrum meter UI does the followings:
- Zoom the album cover proportionality to the current bass value
- Display the 4 bands on the left side of a circle by default at 0°, 45°, 90°, 135°
- Add extra bars next to the "main bars" with a cosine shape. Add more bars for the lower bands.
- If the there is a large enough bass add a random offset to the position of the bars. E.g. start from 63° istead of 0°. (bars greater than 180° start again from 0°)
- If there no bass add 1 to the offset of the bars (it creates a "walking" effect)
- Mirror the bars to the right side of the circle

Using spectrum.py

install librosa with pip3 install librosa
run python sectrum.py my_file.mp3
see the result in spectrum.h