fontbm

BMFont compatible, cross-platform (Linux/macOS/Windows) command line bitmap font generator (FreeType2 based render).

Status

Linux	macOS	Windows

Usage

Download compiled version (fontbm.zip for Windows, fontbm for Linux) from Releases. Run:

fontbm --font-file FreeSans.ttf --output myfont

It will produce myfont.fnt (file format) and myfont_0.png (how to render text).

The metrics file always has the .fnt extension, whatever --data-format is used. Run fontbm --help for the same reference right in the terminal.

Available options (bold options are required):

option	default	comment
--font-file		font to render, .ttf or .otf
--output		output name without extension
--font-size	32	character height in pixels (it matches to BMFont size, when "Match char height" option in Font Settings dialog is ticked)
--chars	32-126	characters to render, as decimal Unicode code points: single values and/or first-last ranges, comma separated (without spaces), for example 32-64,92,120-126; the default is used only if 'chars-file' option is not defined
--chars-file		optional path to UTF-8 text file with additional required characters (will be combined with 'chars' option), can be set multiple times
--texture-size	32x32,64x32,64x64,128x64, 128x128,256x128,256x256, 512x256,512x512,1024x512, 1024x1024,2048x1024,2048x2048	comma separated list of allowed texture sizes as widthxheight (without spaces), tried from left to right, the first one all glyphs fit into is used
--texture-crop-width		shrink every texture page to the rightmost used pixel
--texture-crop-height		shrink every texture page to the lowest used pixel
--max-texture-count		fail if more texture pages than this are needed (unlimited if not set)
--texture-name-suffix	index_aligned	how the page number is added to the .png name: index_aligned (myfont_00.png, zero padded to the highest page number), index (myfont_0.png), none (myfont.png, single page only)
--color	255,255,255	foreground RGB color, decimal 0-255 each, for example: 32,255,255 (without spaces)
--background-color		background RGB color, decimal 0-255 each, for example: 0,0,128 (without spaces), transparent by default
--monochrome		disable anti-aliasing
--data-format	txt	output data file format: txt, xml, bin, json (the extension stays .fnt in every case)
--kerning-pairs	disabled	generate kerning pairs: disabled, basic, regular (tuned by hinter), extended (bigger output size, but more precise)
--padding-up	0	pixels added above each glyph, inside its rectangle
--padding-right	0	pixels added right of each glyph, inside its rectangle
--padding-down	0	pixels added below each glyph, inside its rectangle
--padding-left	0	pixels added left of each glyph, inside its rectangle
--spacing-vert	0	pixels left between glyph rectangles, vertically
--spacing-horiz	0	pixels left between glyph rectangles, horizontally
--align-horiz	1	round glyph rectangle width up to a multiple of this value, must be greater than 0
--align-vert	1	round glyph rectangle height up to a multiple of this value, must be greater than 0
--verbose		print the FreeType version being used
--help		print help and exit

fontbm exits with 0 on success and 1 on error. Errors and warnings are printed to stderr, --help and --verbose output to stdout.

Building Linux

Dependencies:

• GCC-4.9
• CMake 3.10
• FreeType

Build:

cmake .  
make

Building Windows (using vcpkg)

Download and install vcpkg and CMake 3.10.2 (or above). Run:

vcpkg install freetype
cmake -G "Visual Studio 14 2015" -DCMAKE_TOOLCHAIN_FILE=<path to vcpkg dir>/scripts/buildsystems/vcpkg.cmake

Open .sln in Visual Studio 2015 and rebuild all.

Building Windows

Download and install CMake 3.10 (or above) and FreeType. Run:

cmake -G "Visual Studio 14 2015"

Open .sln file in Visual Studio 2015, configure paths to FreeType and rebuild all.

Building macOS

(thanx to andycarle Moddable-OpenSource/moddable#325 (comment))

brew install freetype
brew install cmake
git clone https://github.com/vladimirgamalyan/fontbm.git
cd fontbm
cmake .
make

Using AI agents

fontbm is self-documenting: fontbm --help prints a full reference — every option with its default, the produced files and ready to run examples — so an AI agent can drive it from that output alone. Just point the agent at the binary.

To let an agent reach for fontbm on its own, copy the skills/fontbm directory to your agent's skill directory. It is a thin pointer that tells the agent when fontbm is relevant and sends it to --help for the details. Then ask something like make bitmap font, 24pt, Arial.

Special thanks

• phoddie

License

MIT License

The project also bundles third party software under its own licenses:

• lvandeve/lodepng - PNG encoder and decoder in C and C++ - zlib
• juj/RectangleBinPack - 2d rectangular bin packing - Public Domain
• leethomason/tinyxml2 - a simple, small, efficient, C++ XML parse - zlib
• UTF8-CPP - UTF-8 with C++ in a Portable Way - BSL-1.0
• catchorg/Catch2 - A modern, C++-native, header-only, test framework for unit-tests - BSL-1.0
• jarro2783/cxxopts - Lightweight C++ command line option parser - MIT
• nlohmann/json - JSON for Modern C++ - MIT