File System Interfaces

LVGL has a File system module to provide an abstraction layer for various file system drivers.

LVG has built in support for:

  • FATFS

  • STDIO (Linux and Windows using C standard function .e.g fopen, fread)

  • POSIX (Linux and Windows using POSIX function .e.g open, read)

  • WIN32 (Windows using Win32 API function .e.g CreateFileA, ReadFile)

  • MEMFS (read a file from a memory buffer)

  • LITTLEFS (a little fail-safe filesystem designed for microcontrollers)

You still need to provide the drivers and libraries, this extension provides only the bridge between FATFS, STDIO, POSIX, WIN32 and LVGL.

Usage

In lv_conf.h enable LV_USE_FS_... and assign an upper cased letter to LV_FS_..._LETTER (e.g. 'S'). After that you can access files using that driver letter. E.g. "S:path/to/file.txt".

The work directory can be set with LV_FS_..._PATH. E.g. "/home/joe/projects/" The actual file/directory paths will be appended to it.

Cached reading is also supported if LV_FS_..._CACHE_SIZE is set to not 0 value. lv_fs_read() caches this size of data to lower the number of actual reads from the storage.

To use the memory-mapped file emulation an lv_fs_path_ex_t object must be created and initialized. This object can be passed to lv_fs_open() as the file name:

lv_fs_path_ex_t mempath;
lv_fs_file_t file;
uint8_t *buffer;
uint32_t size;

/*Initialize buffer*/
...

lv_fs_make_path_from_buffer(&mempath, LV_FS_MEMFS_LETTER, (void*)buffer, size);
lv_fs_res_t res = lv_fs_open(&file, (const char *)&mempath, LV_FS_MODE_RD);

API

lv_fs.h