lvgl/docs/libs/freetype.md

# FreeType support
Interface to [FreeType](https://www.freetype.org/) to generate font bitmaps run time.

## Add FreeType to your project

First, Download FreeType from [here](https://sourceforge.net/projects/freetype/files/).

There are two ways to use FreeType:
### For UNIX
For UNIX systems, it is recommended to use the way of compiling and installing libraries.
- Enter the FreeType source code directory.
- `make`
- `sudo make install`
- Add include path: `/usr/include/freetype2` (for GCC: `-I/usr/include/freetype2 -L/usr/local/lib`)
- Link library: `freetype` (for GCC: `-L/usr/local/lib -lfreetype`)

### For Embedded Devices
For embedded devices, it is more recommended to use the FreeType configuration file provided by LVGL, which only includes the most commonly used functions, which is very meaningful for saving limited FLASH space.

- Copy the FreeType source code to your project directory.
- Refer to the following `Makefile` for configuration:

```make
# FreeType custom configuration header file
CFLAGS += -DFT2_BUILD_LIBRARY
CFLAGS += -DFT_CONFIG_MODULES_H=<lvgl/src/libs/freetype/ftmodule.h>
CFLAGS += -DFT_CONFIG_OPTIONS_H=<lvgl/src/libs/freetype/ftoption.h>

# FreeType include path
CFLAGS += -Ifreetype/include

# FreeType C source file
FT_CSRCS += freetype/src/base/ftbase.c
FT_CSRCS += freetype/src/base/ftbitmap.c
FT_CSRCS += freetype/src/base/ftdebug.c
FT_CSRCS += freetype/src/base/ftglyph.c
FT_CSRCS += freetype/src/base/ftinit.c
FT_CSRCS += freetype/src/cache/ftcache.c
FT_CSRCS += freetype/src/gzip/ftgzip.c
FT_CSRCS += freetype/src/sfnt/sfnt.c
FT_CSRCS += freetype/src/smooth/smooth.c
FT_CSRCS += freetype/src/truetype/truetype.c
CSRCS += $(FT_CSRCS)
```

## Usage
Enable `LV_USE_FREETYPE` in `lv_conf.h`.

Cache configuration:
- `LV_FREETYPE_CACHE_SIZE` - Maximum memory(Bytes) used to cache font bitmap, outline, character maps, etc. **Note:** This value does not include the memory used by 'FT_Face' and 'FT_Size' objects
- `LV_FREETYPE_CACHE_FT_FACES` - Maximum open number of `FT_Face` objects.
- `LV_FREETYPE_CACHE_FT_SIZES` - Maximum open number of `FT_Size` objects.

When you are sure that all the used font sizes will not be greater than 256, you can enable `LV_FREETYPE_SBIT_CACHE`, which is much more memory efficient for small bitmaps.

By default, the FreeType extension doesn't use LVGL's file system.
You can simply pass the path to the font as usual on your operating system or platform.

If you want FreeType to use lvgl's memory allocation and file system interface, you can enable `LV_FREETYPE_USE_LVGL_PORT` in `lv_conf.h`, convenient for unified management.

The font style supports *Italic* and **Bold** fonts processed by software, and can be set with reference to the following values:
- `LV_FREETYPE_FONT_STYLE_NORMAL` - Default style.
- `LV_FREETYPE_FONT_STYLE_ITALIC` - Italic style.
- `LV_FREETYPE_FONT_STYLE_BOLD` - Bold style.

They can be combined.eg: `LV_FREETYPE_FONT_STYLE_BOLD | LV_FREETYPE_FONT_STYLE_ITALIC`.

Use the `lv_freetype_font_create()` function to create a font. To delete a font, use `lv_freetype_font_del()`. For more detailed usage, please refer to example code.

## Example
```eval_rst
.. include:: ../../examples/libs/freetype/index.rst
```


## Learn more
- FreeType [tutorial](https://www.freetype.org/freetype2/docs/tutorial/step1.html)
- LVGL's [font interface](https://docs.lvgl.io/master/overview/font.html#add-a-new-font-engine)


## API
```eval_rst
.. doxygenfile:: lv_freetype.h
  :project: lvgl
```