msdf-bmfont-xml

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.

Run script to see MSDF font in browser using pixi.js

npm install & npm run render

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

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

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

Options:
  -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, font.data, (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) => {
  ...
});

API

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.

Options:

• 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
  • font.data stringified xml\json data to be written to disk

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

License

MIT, see LICENSE.md for details.