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Converts a .ttf font file into multichannel signed distance fields, then outputs packed spritesheets and a xml(.fnt} or json representation of an AngelCode BMfont.

Signed distance fields are a method of reproducing vector shapes from a texture representation, popularized in this paper by Valve. This tool uses Chlumsky/msdfgen to generate multichannel signed distance fields to preserve corners. The distance fields are created from vector fonts, then rendered into texture pages. A BMFont object is provided for character layout.

Preview image

Install as CLI

npm install msdf-bmfont-xml -g

Then you just need to call msdf-bmfont from console to generate font file. Type in msdf-bmfont --help for more detail usage.



Usage: msdf-bmfont [options] <font-file>

Creates a BMFont compatible bitmap font of signed distance fields from a font file

  -V, --version                 output the version number
  -f, --output-type <format>    font file format: xml(default) | json (default: "xml")
  -o, --filename <atlas_path>   filename of font textures (defaut: font-face)
                                font filename always set to font-face name
  -s, --font-size <fontSize>    font size for generated textures (default: 42)
  -i, --charset-file <charset>  user-specified charactors from text-file
  -m, --texture-size <w,h>      ouput texture atlas size (default: [2048,2048])
  -p, --texture-padding <n>     padding between glyphs (default: 1)
  -b, --border <n>              space between glyphs textures & edge (default: 0)
  -r, --distance-range <n>      distance range for SDF (default: 4)
  -t, --field-type <type>       msdf(default) | sdf | psdf (default: "msdf")
  -d, --round-decimal <digit>   rounded digits of the output font file. (default: 0)
  -v, --vector                  generate svg vector file for debuging
  -u, --reuse [file.cfg]        save/create config file for reusing settings (default: false)
      --smart-size              shrink atlas to the smallest possible square
      --pot                     atlas size shall be power of 2
      --square                  atlas size shall be square
      --rot                     allow 90-degree rotation while packing
      --rtl                     use RTL(Arabic/Persian) charactors fix
  -h, --help                    output usage information

CLI Examples

Generate a multi-channel signed distance field font atlas with ASCII charset, font size 42, spread 3, maximum texture size 512x256, padding 1, and save out config file:

msdf-bmfont --reuse -o path/to/atlas.png -m 512,256 -s 42 -r 3 -p 1 -t msdf path/to/font.ttf

We will get three file: atlas.0.png atlas.0.cfg & font.fnt and this is the generated atlas in the minimum pot size (256x256):


Then we want to use the old setting except a different font and use monochrome signed distance field atlas, and output an extra .svg version of atlas:

msdf-bmfont -v -u path/to/atlas.0.cfg -t sdf -p 0 -r 8 path/to/anotherfont.ttf

This time we get a modified atlas.0.png with new bitmap font appended:


Not satisfied with the style? Remember we got a svg atlas!


How about fire up some graphic editor and add some neat effect and lay on the output atlas?


Install as Module

npm install msdf-bmfont-xml

Module usage Examples

Writing the distance fields and font data to disk:

const generateBMFont = require('msdf-bmfont-xml');
const fs = require('fs');

generateBMFont('Some-Font.ttf', (error, textures, font) => {
  if (error) throw error;
  textures.forEach((texture, index) => {
    fs.writeFile(texture.filename, texture.texture, (err) => {
      if (err) throw err;
  fs.writeFile(font.filename,, (err) => {
    if (err) throw err;

Generating a single channel signed distance field with a custom character set:

const generateBMFont = require('msdf-bmfont');

const opt = {
  charset: 'ABC.ez_as-123!',
  fieldType: 'sdf'
generateBMFont('Some-Font.ttf', opt, (error, textures, font) => {


generateBMFont(fontPath | fontBuffer, [opt], callback)

Renders a bitmap font from the font specified by fontPath or fontBuffer, with optional opt settings, triggering callback on complete.


  • outputType (String)
    • type of output font file. Defaults to xml
      • xml a BMFont standard .fnt file which is wildly supported.
      • json a JSON file compatible with Hiero
  • filename (String)
    • filename of both font file and font atlas. If omited, font face name is used. Required if font is provided as a Buffer.
  • charset (String|Array)
    • the characters to include in the bitmap font. Defaults to all ASCII printable characters.
  • fontSize (Number)
    • the font size at which to generate the distance field. Defaults to 42
  • textureSize (Array[2])
    • the dimensions of an output texture sheet, normally power-of-2 for GPU usage. Both dimensions default to [512, 512]
  • texturePadding (Number)
    • pixels between each glyph in the texture. Defaults to 2
  • border (Number)
    • space between glyphs textures & edge. Defaults to 0
  • fieldType (String)
    • what kind of distance field to generate. Defaults to msdf. Must be one of:
      • msdf Multi-channel signed distance field
      • sdf Monochrome signed distance field
      • psdf monochrome signed pseudo-distance field
  • distanceRange (Number)
    • the width of the range around the shape between the minimum and maximum representable signed distance in pixels, defaults to 3
  • roundDecimal (Number)
    • rounded digits of the output font metics. For xml output, roundDecimal: 0 recommended.
  • vector (Boolean)
    • output a SVG Vector file for debugging. Defauts to false
  • smart-size (Boolean)
    • shrink atlas to the smallest possible square. Default: false
  • pot (Boolean)
    • output atlas size shall be power of 2. Default: false
  • square (Boolean)
    • output atlas size shall be square. Default: false
  • rot (Boolean)
    • allow 90-degree rotation while packing. Default: false
  • rtl (Boolean)
    • use RTL(Arabic/Persian) charators fix. Default: false

The callback is called with the arguments (error, textures, font)

  • error on success will be null/undefined
  • textures an array of js objects of texture spritesheet.
    • textures[index].filename Spritesheet filename
    • textures[index].texture Image Buffers, containing the PNG data of one texture sheet
  • font an object containing the BMFont data, to be used to render the font
    • font.filename font filename
    • stringified xml\json data to be written to disk

Since opt is optional, you can specify callback as the second argument.


MIT, see for details.


Generate BMFont texture and spec XML using msdfgen




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