Windows/Linux 给 lvgl8 添加本地文件系统支持。

whycan晕哥 LV 9

注册lvgl文件系统

void init_fs_config(void)
{
    static lv_fs_drv_t pcfs_drv;                         /*A driver descriptor*/
    lv_fs_drv_init(&pcfs_drv);
    pcfs_drv.user_data = NULL;
    pcfs_drv.letter = 'P';
    pcfs_drv.ready_cb = pcfs_ready;
    pcfs_drv.write_cb = pcfs_write;
    pcfs_drv.open_cb = pcfs_open;
    pcfs_drv.close_cb = pcfs_close;
    pcfs_drv.read_cb = pcfs_read;
    pcfs_drv.seek_cb = pcfs_seek;
    pcfs_drv.tell_cb = pcfs_tell;
    lv_fs_drv_register(&pcfs_drv);
}

文件系统是否准备好被回调函数pcfs_ready

bool pcfs_ready(lv_fs_drv_t* drv)
{
    (void)drv; /*Unused*/
    return true;  //这里仅返回true,如果是嵌入式，则是返回嵌入式文件系统挂载成功与否的标志
}

打开文件被回调的函数pcfs_open

static void* pcfs_open(lv_fs_drv_t* drv, const char* fn, lv_fs_mode_t mode)
{
    (void)drv; /*Unused*/

    errno = 0;

    const char* flags = "";

    if (mode == LV_FS_MODE_WR) flags = "wb";
    else if (mode == LV_FS_MODE_RD) flags = "rb";
    else if (mode == (LV_FS_MODE_WR | LV_FS_MODE_RD)) flags = "a+";

    /*Make the path relative to the current directory (the projects root folder)*/
    char buf[256];
    sprintf(buf, "./%s", fn);

    return fopen(buf, flags);  
}

写入文件被回调的函数pcfs_write

static lv_fs_res_t pcfs_write(struct _lv_fs_drv_t* drv, void* file_p, const void* buf, uint32_t btw, uint32_t* bw)
{
    (void)drv; /*Unused*/

    *bw = (uint32_t)fwrite(buf, 1, btw, file_p);

    return LV_FS_RES_OK;
}

读取文件被回调的函数pcfs_read

static lv_fs_res_t pcfs_read(lv_fs_drv_t* drv, void* file_p, void* buf, uint32_t btr, uint32_t* br)
{
    (void)drv; /*Unused*/
    
    //pc_file_t* fp = file_p;        /*Just avoid the confusing casings*/
    *br = (uint32_t)fread(buf, 1, btr, file_p);
    return LV_FS_RES_OK;
}

关闭文件被回调的函数pcfs_close

static lv_fs_res_t pcfs_close(lv_fs_drv_t* drv, void* file_p)
{
    (void)drv; /*Unused*/

    return fclose(file_p);
}

移动文件位置被回调的函数pcfs_seek

static lv_fs_res_t pcfs_seek(lv_fs_drv_t* drv, void* file_p, uint32_t pos,lv_fs_whence_t whence)
{
    (void)drv; /*Unused*/

    return fseek(file_p, pos, whence);
}

获取文件位置被回调的函数pcfs_tell

static lv_fs_res_t pcfs_tell(lv_fs_drv_t* drv, void* file_p, uint32_t* pos_p)
{
    (void)drv; /*Unused*/
    *pos_p = ftell(file_p);
    return LV_FS_RES_OK;
}

初时化调用init_fs_config函数

init_fs_config();

加载外部图片

    lv_obj_t* obj = lv_img_create(lv_scr_act());
    lv_img_set_src(obj, "P:/lock_icon.bin");
    lv_obj_center(obj);

效果图

加载外部字体需要匹配读取数据函数

static uint8_t __g_font_buf[364];//如bin文件存在SPI FLASH可使用此buff
static uint8_t *__user_font_getdata(int offset, int size){
    //如字模保存在SPI FLASH, SPIFLASH_Read(__g_font_buf,offset,size);
    //如字模已加载到SDRAM,直接返回偏移地址即可如:return (uint8_t*)(sdram_fontddr+offset);
    lv_fs_file_t file;
    lv_fs_res_t result;
    result = lv_fs_open(&file, "P:/myFont.bin", LV_FS_MODE_RD);
    if (result != LV_FS_RES_OK)
        return NULL;

    lv_fs_seek(&file, offset, LV_FS_SEEK_CUR);
    uint32_t len;
    lv_fs_read(&file, __g_font_buf, size, &len);
    lv_fs_close(&file);
    return __g_font_buf;
}

使用外部字显示

    lv_obj_t* obj = lv_btn_create(lv_scr_act());
    lv_obj_set_size(obj, 300, 300);
    lv_obj_center(obj);

    lv_obj_t* label = lv_label_create(obj);
    lv_obj_set_style_text_font(label, &_myFont, 0);
    lv_label_set_text(label, "外部字体测试");
    lv_obj_center(label);

中文内容需要utf-8格式编译

#pragma execution_character_set("utf-8") `

whycan晕哥 LV 9

用这代码，显示本地 gif 图片成功。

xfdr0805 LV 5

@whycan lvgl本身就支持吧，只要在lv_config.h配置一下就可以用了
*---------------------

3rd party libraries
--------------------/

/*File system interfaces for common APIs
To enable set a driver letter for that API/
#define LV_USE_FS_STDIO '\0' /Uses fopen, fread, etc/
//#define LV_FS_STDIO_PATH "/home/john/" /*Set the working directory. If commented it will be "./" */

#define LV_USE_FS_POSIX 1 /Uses open, read, etc/
#define CONFIG_LV_FS_POSIX_LETTER 'S' /Uses open, read, etc/
//#define LV_FS_POSIX_PATH "/" /*Set the working directory. If commented it will be "./" */

#define LV_USE_FS_WIN32 '\0' /Uses CreateFile, ReadFile, etc/
//#define LV_FS_WIN32_PATH "C:\Users\john\" /*Set the working directory. If commented it will be ".\" */

#define LV_USE_FS_FATFS '\0' /Uses f_open, f_read, etc/

whycan晕哥 LV 9

@xfdr0805
感谢指教, 我搜索了一下本地文件确实没有, 是比较旧的 v8.0.x

看了一下主线, 真有了:

https://github.com/lvgl/lvgl/commits/master/src/extra/libs/fsdrv/lv_fs_posix.c

https://github.com/lvgl/lvgl/blob/master/lv_conf_template.h