Linux移植LVGL

Linux移植LVGL

参考：https://mp.weixin.qq.com/s?__biz=MzAxNTAyOTczMw==&mid=2649344034&idx=1&sn=6782bcb407e8dad790b1931176c9f4b6&chksm=83972ca8b4e0a5bef0ba61cd4370a2471b4b3d794ef2dd144b3692d32c9f78d7a6b7c5c24c5b&scene=27

1 开始前必须搭建好Linux的交叉编译环境。

2 准备lvgl源码

名称	仓库地址	描述
lvgl	https://github.com/lvgl/lvgl.git	包含了LVGL图形界面控件的源码以及少量例程，lvgl-8.3.5
lv_drivers	https://github.com/lvgl/lv_drivers.git	包含了驱动LVGL图形界面的驱动接口源代码，lv_drivers-6.1.1
lv_port_linux_frame_buffer	https://github.com/lvgl/lv_port_linux_frame_buffer.git	适配有frame buffer的linux系统的接口

**注意：**从仓库下载代码的时候选择Release版本

3 组织移植相关的文件

3.1 建立一个文件夹用于存放整个工程，lvgl_demo_doc

3.2 将相关文件拷贝到新建的目录中（将文件夹后面的版本号删除），其中包括：

• lvgl文件夹 => lvgl_demo_doc

• lv_drivers文件夹 => lvgl_demo_doc

• lv_port_linux_frame_buffer文件夹中的main.c => lvgl_demo_doc

• lv_port_linux_frame_buffer文件夹中的Makefile => lvgl_demo_doc

• lvgl/lv_conf_template.h => lvgl_demo_doc/lv_conf.h(去掉template)

• lv_drivers/lv_drv_conf_template.h => lvgl_demo_doc/lv_drv_conf.h(去掉template)

  3.3 整理好的文件夹应该有如下6个文件

root@ubuntu:/mnt/hgfs/VMware/forlinx/workspace/lvgl_demo_doc# ls -l
total 49
-rwxrwxrwx 1 root root 25825 Feb  6 23:12 lv_conf.h
drwxrwxrwx 1 root root  4096 Feb 18 00:03 lv_drivers
-rwxrwxrwx 1 root root 11196 Jan  3  2020 lv_drv_conf.h
drwxrwxrwx 1 root root  4096 Feb 18 00:03 lvgl
-rwxrwxrwx 1 root root  2350 Feb 16 23:35 main.c
-rwxrwxrwx 1 root root  2000 Feb 16 23:35 Makefile

4 修改文件

4.1 修改lv_drv_conf.h

• 将文件最开始的#if 0改为#if 1

/**
 * @file lv_drv_conf.h
 *
 */

/*
 * COPY THIS FILE AS lv_drv_conf.h
 */

#if 1 /*Set it to "1" to enable the content*/

#ifndef LV_DRV_CONF_H
#define LV_DRV_CONF_H

#include "lv_conf.h"

• 将宏USE_FBDEV的值改为1，使能frame buffer设备

/*-----------------------------------------
 *  Linux frame buffer device (/dev/fbx)
 *-----------------------------------------*/
#ifndef USE_FBDEV
#  define USE_FBDEV           1
#endif

#if USE_FBDEV
#  define FBDEV_PATH          "/dev/fb0"
#endif

• 将宏USE_EVDEV使能为1，并且触控输入设备的名称要根据自己的板子实际情况更改.(如果板子触摸坐标跟实际的坐标方向和比例不一样，通过EVDEV_SCALE和EVDEV_CALIBRATE这两个宏里面的参数修改)

/*-------------------------------------------------
 * Mouse or touchpad as evdev interface (for Linux based systems)
 *------------------------------------------------*/
#ifndef USE_EVDEV
#  define USE_EVDEV           1
#endif

#if USE_EVDEV
#  define EVDEV_NAME   "/dev/input/event1"        /*You can use the "evtest" Linux tool to get the list of devices and test them*/
#  define EVDEV_SWAP_AXES         0               /*Swap the x and y axes of the touchscreen*/

#  define EVDEV_SCALE             1               /* Scale input, e.g. if touchscreen resolution does not match display resolution */
#  if EVDEV_SCALE
#    define EVDEV_SCALE_HOR_RES     (1024)          /* Horizontal resolution of touchscreen */
#    define EVDEV_SCALE_VER_RES     (600)          /* Vertical resolution of touchscreen */
#  endif  /*EVDEV_SCALE*/

#  define EVDEV_CALIBRATE         1               /*Scale and offset the touchscreen coordinates by using maximum and minimum values for each axis*/
#  if EVDEV_CALIBRATE
#    define EVDEV_HOR_MIN   800                    /*If EVDEV_XXX_MIN > EVDEV_XXX_MAX the XXX axis is automatically inverted*/
#    define EVDEV_HOR_MAX   0
#    define EVDEV_VER_MIN   480
#    define EVDEV_VER_MAX   0
#  endif  /*EVDEV_SCALE*/
#endif  /*USE_EVDEV*/

4.2 修改lv_conf.h

• 将文件最开始的#if 0改为#if 1

/* clang-format off */
#if 1 /*Set it to "1" to enable content*/

#ifndef LV_CONF_H
#define LV_CONF_H

#include 

• 使能宏LV_MEM_CUSTOM为1

/*=========================
   MEMORY SETTINGS
 *=========================*/

/*1: use custom malloc/free, 0: use the built-in `lv_mem_alloc()` and `lv_mem_free()`*/
#define LV_MEM_CUSTOM 1
#if LV_MEM_CUSTOM == 0
    /*Size of the memory available for `lv_mem_alloc()` in bytes (>= 2kB)*/
    #define LV_MEM_SIZE (48U * 1024U)          /*[bytes]*/

    /*Set an address for the memory pool instead of allocating it as a normal array. Can be in external SRAM too.*/
    #define LV_MEM_ADR 0     /*0: unused*/
    /*Instead of an address give a memory allocator that will be called to get a memory pool for LVGL. E.g. my_malloc*/
    #if LV_MEM_ADR == 0
        #undef LV_MEM_POOL_INCLUDE
        #undef LV_MEM_POOL_ALLOC
    #endif

#else       /*LV_MEM_CUSTOM*/
    #define LV_MEM_CUSTOM_INCLUDE <stdlib.h>   /*Header for the dynamic memory function*/
    #define LV_MEM_CUSTOM_ALLOC   malloc
    #define LV_MEM_CUSTOM_FREE    free
    #define LV_MEM_CUSTOM_REALLOC realloc
#endif     /*LV_MEM_CUSTOM*/

• 最后是比较关键的一个设置，TICK的配置，我们选择自己定义一个Tick定时器配置函数，在自己的应用程序中实现：

#if 0	//原始代码
/*Use a custom tick source that tells the elapsed time in milliseconds.
 *It removes the need to manually update the tick with `lv_tick_inc()`)*/
#define LV_TICK_CUSTOM 0
#if LV_TICK_CUSTOM
    #define LV_TICK_CUSTOM_INCLUDE "Arduino.h"         /*Header for the system time function*/
    #define LV_TICK_CUSTOM_SYS_TIME_EXPR (millis())    /*Expression evaluating to current system time in ms*/
    /*If using lvgl as ESP32 component*/
    // #define LV_TICK_CUSTOM_INCLUDE "esp_timer.h"
    // #define LV_TICK_CUSTOM_SYS_TIME_EXPR ((esp_timer_get_time() / 1000LL))
#endif   /*LV_TICK_CUSTOM*/

#else	//新代码
/*Use a custom tick source that tells the elapsed time in milliseconds.
 *It removes the need to manually update the tick with `lv_tick_inc()`)*/
#define LV_TICK_CUSTOM 1
#if LV_TICK_CUSTOM
    #define LV_TICK_CUSTOM_INCLUDE <stdint.h>         /*Header for the system time function*/
    #define LV_TICK_CUSTOM_SYS_TIME_EXPR (custom_tick_get())    /*Expression evaluating to current system time in ms*/
#endif   /*LV_TICK_CUSTOM*/
#endif

• 使能widget例程

  /*Show some widget. It might be required to increase `LV_MEM_SIZE` */
  #define LV_USE_DEMO_WIDGETS 1
  #if LV_USE_DEMO_WIDGETS
  #define LV_DEMO_WIDGETS_SLIDESHOW 0
  #endif
  

4.3 修改main.c

• 我们没有将lvgl的demos移植到工程文件中，所以需要将demos头文件注释掉

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

• 根据自己的屏幕调整分辨率

    disp_drv.hor_res    = 1024;
    disp_drv.ver_res    = 600;

• 没有移植鼠标样式，将鼠标相关的代码屏蔽掉

    // /*Set a cursor for the mouse*/
    // LV_IMG_DECLARE(mouse_cursor_icon)
    // lv_obj_t * cursor_obj = lv_img_create(lv_scr_act()); /*Create an image object for the cursor */
    // lv_img_set_src(cursor_obj, &mouse_cursor_icon);           /*Set the image source*/
    // lv_indev_set_cursor(mouse_indev, cursor_obj);             /*Connect the image  object to the driver*/

4.4修改Makefile

• 查看自己的交叉编译器

  $ echo $CROSS_COMPILE
  arm-poky-linux-gnueabi-
  

• 修改Makefile中的交叉编译器为自己的编译器

  #CC ?= gcc
  CC ?= arm-poky-linux-gnueabi-gcc
  

• 注释掉鼠标样式相关的代码

  #CSRCS +=$(LVGL_DIR)/mouse_cursor_icon.c
  

4.5 修改fbdev.c文件

• 修改void fbdev_init(void)函数中的 screensize 的赋值，不然会使系统崩溃（很重要）

  screensize = finfo.line_length * vinfo.yres;  
  

5 编译

5.1 make编译

• 在lvgl_demo_doc目录下输入make命令

5.2 报错处理

• 错误1，解决方案：去fbdev.h中将#include "lvgl/lvgl.h"改为#include "../../lvgl/lvgl.h"

• 报错2，解决方案：去evdev.h中将#include "lvgl/lvgl.h"改为#include "../../lvgl/lvgl.h"

6 运行

6.1 将程序拷贝到板子中

• 将编译出来的demo可执行文件拷贝到开发板中运行。
• 可以通过U盘拷贝也可以通过nfs挂载方式，推荐使用nfs挂载。

6.2 运行

./demo   //运行

7 运行效果

7.1 显示效果如下

这是因为lv_conf.h中的LV_COLOR_DEPTH没有设置对，按照如下代码修改。

#define LV_COLOR_DEPTH 32

7.2 正确的显示效果