# lv_font_fmt_txt.h (/api/public/font/lv_font_fmt_txt_h)
Functions [#functions]
lv_font_get_bitmap_fmt_txt [#lv_font_get_bitmap_fmt_txt]
Used as `get_glyph_bitmap` callback in lvgl's native font format if the font is uncompressed.
```c title=" " lineNumbers=1
const void * lv_font_get_bitmap_fmt_txt(lv_font_glyph_dsc_t *g_dsc, lv_draw_buf_t *draw_buf)
```
Parameters
| Name | Type | Description |
| ---------- | ---------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| `g_dsc` | | the glyph descriptor including which font to use, which supply the glyph\_index and format. |
| `draw_buf` | | a draw buffer that can be used to store the bitmap of the glyph. **May** be `NULL`. It's OK not to use it. |
**Returns:** `const void *` — pointer to an A8 bitmap (not necessarily bitmap\_out) or NULL if `unicode_letter` not found
lv_font_get_glyph_dsc_fmt_txt [#lv_font_get_glyph_dsc_fmt_txt]
Used as `get_glyph_dsc` callback in lvgl's native font format if the font is uncompressed.
```c title=" " lineNumbers=1
bool lv_font_get_glyph_dsc_fmt_txt(const lv_font_t *font, lv_font_glyph_dsc_t *dsc_out, uint32_t unicode_letter, uint32_t unicode_letter_next)
```
Parameters
| Name | Type | Description |
| --------------------- | ---------------------------------------------------------------------- | --------------------------------------------------- |
| `font` | | pointer to font |
| `dsc_out` | | store the result descriptor here |
| `unicode_letter` | `uint32_t` | a UNICODE letter code |
| `unicode_letter_next` | `uint32_t` | the unicode letter succeeding the letter under test |
**Returns:** `bool` — true: descriptor is successfully loaded into `dsc_out`. false: the letter was not found, no data is loaded to `dsc_out`.
Enums [#enums]
lv_font_fmt_txt_cmap_type_t [#lv_font_fmt_txt_cmap_type_t]
Format of font character map.
| Name |
| ----------------------------------- |
| `LV_FONT_FMT_TXT_CMAP_FORMAT0_FULL` |
| `LV_FONT_FMT_TXT_CMAP_SPARSE_FULL` |
| `LV_FONT_FMT_TXT_CMAP_FORMAT0_TINY` |
| `LV_FONT_FMT_TXT_CMAP_SPARSE_TINY` |
lv_font_fmt_txt_bitmap_format_t [#lv_font_fmt_txt_bitmap_format_t]
Bitmap formats
| Name | Value |
| ----------------------------------------- | ----- |
| `LV_FONT_FMT_TXT_PLAIN` | `0` |
| `LV_FONT_FMT_TXT_COMPRESSED` | `1` |
| `LV_FONT_FMT_TXT_COMPRESSED_NO_PREFILTER` | `2` |
Structs [#structs]
lv_font_fmt_txt_glyph_dsc_t [#lv_font_fmt_txt_glyph_dsc_t]
This describes a glyph.
| Member | Type | Description |
| -------------- | ---------- | ------------------------------------------------------------------------------- |
| `bitmap_index` | `uint32_t` | Start index of the bitmap. A font can be max 1 MB. |
| `adv_w` | `uint32_t` | Draw the next glyph after this width. 8.4 format (real\_value \* 16 is stored). |
| `box_w` | `uint8_t` | Width of the glyph's bounding box |
| `box_h` | `uint8_t` | Height of the glyph's bounding box |
| `ofs_x` | `int8_t` | x offset of the bounding box |
| `ofs_y` | `int8_t` | y offset of the bounding box. Measured from the top of the line |
lv_font_fmt_txt_cmap_t [#lv_font_fmt_txt_cmap_t]
Map codepoints to a `glyph_dsc`s Several formats are supported to optimize memory usage See [https://github.com/lvgl/lv\_font\_conv/blob/master/doc/font\_spec.md](https://github.com/lvgl/lv_font_conv/blob/master/doc/font_spec.md)
| Member | Type | Description |
| ------------------- | ---------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
| `range_start` | `uint32_t` | First Unicode character for this range |
| `range_length` | `uint16_t` | Number of Unicode characters related to this range. Last Unicode character = range\_start + range\_length - 1 |
| `glyph_id_start` | `uint16_t` | First glyph ID (array index of `glyph_dsc`) for this range |
| `unicode_list` | `const uint16_t *` | |
| `glyph_id_ofs_list` | `const void *` | if(type == LV\_FONT\_FMT\_TXT\_CMAP\_FORMAT0\_...) it's `uint8_t *` if(type == LV\_FONT\_FMT\_TXT\_CMAP\_SPARSE\_...) it's `uint16_t *` |
| `list_length` | `uint16_t` | Length of `unicode_list` and/or `glyph_id_ofs_list` |
| `type` | | Type of this character map |
lv_font_fmt_txt_kern_pair_t [#lv_font_fmt_txt_kern_pair_t]
A simple mapping of kern values from pairs
| Member | Type | Description |
| ---------------- | ---------------- | ------------------------------------------------------- |
| `glyph_ids` | `const void *` | |
| `values` | `const int8_t *` | |
| `pair_cnt` | `uint32_t` | |
| `glyph_ids_size` | `uint32_t` | 0: `glyph_ids` is stored as `uint8_t`; 1: as `uint16_t` |
lv_font_fmt_txt_kern_classes_t [#lv_font_fmt_txt_kern_classes_t]
More complex but more optimal class based kern value storage
| Member | Type | Description |
| --------------------- | ----------------- | -------------------------------------------------------------- |
| `class_pair_values` | `const int8_t *` | left\_class\_cnt \* right\_class\_cnt value |
| `left_class_mapping` | `const uint8_t *` | Map the glyph\_ids to classes: index -> glyph\_id -> class\_id |
| `right_class_mapping` | `const uint8_t *` | Map the glyph\_ids to classes: index -> glyph\_id -> class\_id |
| `left_class_cnt` | `uint8_t` | |
| `right_class_cnt` | `uint8_t` | |
lv_font_fmt_txt_dsc_t [#lv_font_fmt_txt_dsc_t]
Describe store for additional data for fonts
| Member | Type | Description |
| --------------------------- | -------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `glyph_bitmap` | `const uint8_t *` | The bitmaps of all glyphs or a lv\_font\_fmt\_txt\_glyph\_loader\_t \* depending on the state of `are_glyphs_dynamic_loaded` a uint8\_t to preserve backwards compatibility |
| `glyph_dsc` | | Describe the glyphs |
| `cmaps` | | Map the glyphs to Unicode characters. Array of `lv_font_cmap_fmt_txt_t` variables |
| `kern_dsc` | `const void *` | Store kerning values. Can be \* or \* depending on `kern_classes` |
| `kern_scale` | `uint16_t` | Scale kern values in 12.4 format |
| `cmap_num` | `uint16_t` | Number of cmap tables |
| `bpp` | `uint8_t` | Bit per pixel: 1, 2, 3, 4, 8 |
| `kern_classes` | `uint8_t` | Type of `kern_dsc` |
| `bitmap_format` | `uint8_t` | storage format of the bitmap from `lv_font_fmt_txt_bitmap_format_t` |
| `stride` | `uint8_t` | Bytes to which each line is padded. 0: means no align and padding 1: e.g. with bpp=4 lines are aligned to 1 byte, so there can be a 4 bits of padding 4, 8, 16, 32, 64: each line is padded to the given byte boundaries |
| `are_glyphs_dynamic_loaded` | `bool` | `false`: the glyph bitmaps are stored in `glyph_bitmap`
`true`: the glyph bitmaps are loaded on demand and `glyph_bitmap` holds a `lv_font_fmt_txt_glyph_loader_t *` instead |
* `lv_draw_eve_label_upload_glyph` — param `font_dsc`
lv_builtin_font_src_t [#lv_builtin_font_src_t]
| Member | Type | Description |
| -------- | -------------------------------------------------------- | ------------------------ |
| `font_p` | | Pointer to built-in font |
| `size` | `uint32_t` | |
Typedefs [#typedefs]
lv_font_fmt_txt_glyph_loader_t [#lv_font_fmt_txt_glyph_loader_t]
```c title=" " lineNumbers=1
typedef struct _lv_font_fmt_txt_glyph_loader_t lv_font_fmt_txt_glyph_loader_t
```
Variables [#variables]
lv_builtin_font_class [#lv_builtin_font_class]
```c title=" " lineNumbers=1
const lv_font_class_t lv_builtin_font_class
```
Dependencies [#dependencies]