Fonts

Due to the change from rendering gauges using GDI to DirectX (see Gauge Conversion), fonts are now rendered as bitmaps rather than directly from Windows fonts. To create a bitmap font file (.fnt), use the FontGen tool. Each bitmap font also needs a JSON format file which describes the characters available. FontGen also uses this file to create the bitmap from a Windows font. A typical command line for FontGen is:

fontgen arial.json

Where arial.json looks like this:

{
"in" : [
{
"scale_x" : 64.0,
"scale_y" : 1.0,
"monochrome" : false,
"force_auto_hint" : true,
"font_file_name" : "arial.ttf",
"font_size_ranges" : [
[8, 35]
],
"unicode_ranges" : [
[ 33, 126 ],
[ 160, 255 ],
[ 339, 340 ]
]
}
],
"out_filename" : "arial.fnt"
}

Note that the source TTF file needs to be in the same folder as the JSON file during conversion.

JSON parameters descriptions

in: Array of font descriptors. Multiple fonts can be generated in a single fnt file to optimize texture usage
scale_x and scale_y: Used internally by the font library to scale the image to improve rasterization quality. Note that it does not scale the final texture. (using default is recommended)
force_auto_hint: Used internally by the font library to improve the rasterization especially on small font sizes. (using default is recommended)
monochrome: When true, no alpha will be used on the edge of the font.
font_file_name: Name of the input ttf file to rasterize.
font_size_ranges: Array of ranges of font sizes. The upper range is excluded.
Example:
"font_size_ranges" : [ [10, 13], [20, 23] ]
Will produce glyphs for font sizes 10, 11, 12 and 20, 21, 22
unicode_ranges: Array of ranges of unicode to be generated. The upper range is excluded. To read more about unicodes, you can read the following page: https://en.wikipedia.org/wiki/List_of_Unicode_characters.
Example:
"unicode_ranges" : [ [ 48, 58 ], [ 97, 123 ] ]
Will produce glyphs for characters "0" to "9" and "a" to "z".
out_filename: Name of the output fnt file to generate.