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https://github.com/lvgl/lv_font_conv
Converts TTF/WOFF fonts to compact bitmap format
https://github.com/lvgl/lv_font_conv
c conveter font lvgl ttf woff
Last synced: 2 days ago
JSON representation
Converts TTF/WOFF fonts to compact bitmap format
- Host: GitHub
- URL: https://github.com/lvgl/lv_font_conv
- Owner: lvgl
- License: mit
- Created: 2019-03-21T05:00:20.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-04-04T20:46:38.000Z (7 months ago)
- Last Synced: 2024-04-13T21:41:48.223Z (7 months ago)
- Topics: c, conveter, font, lvgl, ttf, woff
- Language: JavaScript
- Homepage: https://lvgl.io/tools/fontconverter
- Size: 2.79 MB
- Stars: 151
- Watchers: 12
- Forks: 65
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
- Support: support/Dockerfile
Awesome Lists containing this project
README
lv_font_conv - font convertor to compact bitmap format
======================================================
[](https://github.com/lvgl/lv_font_conv/actions)
[](https://www.npmjs.org/package/lv_font_conv)
Converts TTF/WOFF/OTF fonts to __[compact format](https://github.com/lvgl/lv_font_conv/blob/master/doc/font_spec.md)__, suitable for small embedded systems. Main features are:
- Allows bitonal and anti-aliased glyphs (1-4 bits per pixel).
- Preserves kerning info.
- Compression.
- Users can select required glyphs only (subsetting).
- Multiple font sources can be merged.
- Simple CLI interface, easy to integrate into external build systems.
## Install the script
[node.js](https://nodejs.org/en/download/) v14+ required.
Global install of the last version, execute as "lv_font_conv"
```sh
# install release from npm registry
npm i lv_font_conv -g
# install from github's repo, master branch
npm i lvgl/lv_font_conv -g
```
**run via [npx](https://www.npmjs.com/package/npx) without install**
```sh
# run from npm registry
npx lv_font_conv -h
# run from github master
npx github:lvgl/lv_font_conv -h
```
Note, running via `npx` may take some time until modules installed, be patient.
## CLI params
Common:
- `--bpp` - bits per pixel (antialiasing).
- `--size` - output font size (pixels).
- `-o`, `--output` - output path (file or directory, depends on format).
- `--format` - output format.
- `--format dump` - dump glyph images and font info, useful for debug.
- `--format bin` - dump font in binary form (as described in [spec](https://github.com/lvgl/lv_font_conv/blob/master/doc/font_spec.md)).
- `--format lvgl` - dump font in [LVGL](https://github.com/lvgl/lvgl) format.
- `--force-fast-kern-format` - always use more fast kering storage format,
at cost of some size. If size difference appears, it will be displayed.
- `--lcd` - generate bitmaps with 3x horizontal resolution, for subpixel
smoothing.
- `--lcd-v` - generate bitmaps with 3x vertical resolution, for subpixel
smoothing.
- `--use-color-info` - try to use glyph color info from font to create
grayscale icons. Since gray tones are emulated via transparency, result
will be good on contrast background only.
- `--lv-include` - only with `--format lvgl`, set alternate path for `lvgl.h`.
Per font:
- `--font` - path to font file (ttf/woff/woff2/otf). May be used multiple time for
merge.
- `-r`, `--range` - single glyph or range + optional mapping, belongs to
previously declared `--font`. Can be used multiple times. Examples:
- `-r 0x1F450` - single value, dec or hex format.
- `-r 0x1F450-0x1F470` - range.
- `-r '0x1F450=>0xF005'` - single glyph with mapping.
- `-r '0x1F450-0x1F470=>0xF005'` - range with mapping.
- `-r 0x1F450 -r 0x1F451-0x1F470` - 2 ranges.
- `-r 0x1F450,0x1F451-0x1F470` - the same as above, but defined with single `-r`.
- `--symbols` - list of characters to copy (instead of numeric format in `-r`).
- `--symbols 0123456789.,` - extract chars to display numbers.
- `--autohint-off` - do not force autohinting ("light" is on by default).
- `--autohint-strong` - use more strong autohinting (will break kerning).
Additional debug options:
- `--no-compress` - disable built-in RLE compression.
- `--no-prefilter` - disable bitmap lines filter (XOR), used to improve
compression ratio.
- `--no-kerning` - drop kerning info to reduce size (not recommended).
- `--full-info` - don't shorten 'font_info.json' (include pixels data).
## Examples
Merge english from Roboto Regular and icons from Font Awesome, and show debug
info:
`env DEBUG=* lv_font_conv --font Roboto-Regular.ttf -r 0x20-0x7F --font FontAwesome.ttf -r 0xFE00=>0x81 --size 16 --format bin --bpp 3 --no-compress -o output.font`
Merge english & russian from Roboto Regular, and show debug info:
`env DEBUG=* lv_font_conv --font Roboto-Regular.ttf -r 0x20-0x7F -r 0x401,0x410-0x44F,0x451 --size 16 --format bin --bpp 3 --no-compress -o output.font`
Dump all Roboto glyphs to inspect icons and font details:
`lv_font_conv --font Roboto-Regular.ttf -r 0x20-0x7F --size 16 --format dump --bpp 3 -o ./dump`
**Note**. Option `--no-compress` exists temporary, to avoid confusion until LVGL
adds compression support.
## Technical notes
### Supported output formats
1. **bin** - universal binary format, as described in https://github.com/lvgl/lv_font_conv/tree/master/doc.
2. **lvgl** - format for LVGL, C file. Has minor limitations and a bit
bigger size, because C does not allow to effectively define relative offsets
in data blocks.
3. **dump** - create folder with each glyph in separate image, and other font
data as `json`. Useful for debug.
### Merged font metrics
When multiple fonts merged into one, sources can have different metrics. Result
will follow principles below:
1. No scaling. Glyphs will have exactly the same size, as intended by font authors.
2. The same baseline.
3. `OS/2` metrics (`sTypoAscender`, `sTypoDescender`, `sTypoLineGap`) will be
used from the first font in list.
4. `hhea` metrics (`ascender`, `descender`), defined as max/min point of all
font glyphs, are recalculated, according to new glyphs set.
## Development
Current package includes WebAssembly build of FreeType with some helper
functions. Everything is wrapped into Docker and requires zero knowledge about
additional tools install. See `package.json` for additional commands. You may
need those if decide to upgrade FreeType or update helpers.
This builds image with emscripten & freetype, usually should be done only once:
```
npm run build:dockerimage
```
This compiles helpers and creates WebAssembly files:
```
npm run build:freetype
```