libGDX makes use of bitmap files (pngs) to render fonts. Each glyph in the font has a corresponding TextureRegion.

BitmapFont class (code)

BitmapFont was refactored for the libGDX 1.5.6 release. This blog post has details about the changes and also a small example showing how to move from pre 1.5.6 code to the new API.

A tutorial on using BitmapFont is available on LibGDX.info

File format specifications for the font file

References point to bmFont being originally created by Andreas Jönsson over at AngelCode

BMFont - the original specification for the file format.

Glyph Designer - Details about output, include a binary format.

Tools for Creating Bitmaps

Hiero - a utility for converting a system font to a bitmap

ShoeBox - lets you load customized glyphs from an image, and then create a bitmap font from them. There’s a great tutorial for using it with libgdx.

Glyph Designer - a commercial bitmap font tool with a wide variety of options for shadows, gradients, stroke, etc.

Littera - online bitmap font generator, with a great amount of customizations (needs Adobe Flash).

Other Tools

FreeTypeFontGenerator - generating bitmaps for fonts instead of supplying a pre-rendered bitmap made by utilities like Hiero

Examples : (more)

FreeTypeFontGenerator generator = new FreeTypeFontGenerator(Gdx.files.internal("data/unbom.ttf"));
FreeTypeFontParameter parameter = new FreeTypeFontParameter();
parameter.size = 18;
parameter.characters = "한국어/조선�?";
BitmapFont koreanFont = generator.generateFont(parameter);
parameter.characters = FreeTypeFontGenerator.DEFAULT_CHARS;
generator = new FreeTypeFontGenerator(Gdx.files.internal("data/russkij.ttf"));
BitmapFont cyrillicFont = generator.generateFont(parameter);
generator.dispose();

Distance field fonts - useful for scaling/rotating fonts without ugly artifacts

gdx-smart-font - unofficial libGDX addon for automatically generating and caching bitmap fonts based on screen size. (Uses FreeTypeFontGenerator)

Fonts in 3D space

While libGDX does not support placing text in 3D space directly, it is still possible to do so relatively easily. Check this gist for an example. Note that such text won’t be occluded by objects in front of it, as SpriteBatch draws with constant z, but it would not be hard to fix that with a custom shader, that would set the appropriate ‘z’ from an uniform.

Fixed-Width Fonts

Fonts that need to be displayed with the same width for every glyph present a special problem. The initial blank space at left before narrow chars such as | won’t be shown by default, and the narrow char will “cling” to just after the previous char, without the intended blank space. This also can cause issues with the width of that char being smaller, and that makes multiple lines of text unaligned with each other. There’s an existing BitmapFont#setFixedWidthGlyphs(CharSequence) method, which solves all this for the chars you have in the given CharSequence (usually a String). The catch is, you need to list every glyph in the font that needs to have the same width, and this can be a significant hassle for large fonts. If you’re sticking to ASCII or a small extension of it, Hiero has ASCII and NeHe buttons to fill the text field with those common smaller character sets, and you can copy that text into a String you pass to setFixedWidthGlyphs(). If you have a fixed-width font where the list of all chars that you could use is very large or unknown, you can use this code to set every glyph to fixed-width, using the largest glyph width for every glyph:

        public static void setAllFixedWidth(BitmapFont font) {
            BitmapFont.BitmapFontData data = font.getData();
            int maxAdvance = 0;
            for (int index = 0, end = 65536; index < end; index++) {
                BitmapFont.Glyph g = data.getGlyph((char) index);
                if (g != null && g.xadvance > maxAdvance) maxAdvance = g.xadvance;
            }
            for (int index = 0, end = 65536; index < end; index++) {
                BitmapFont.Glyph g = data.getGlyph((char) index);
                if (g == null) continue;
                g.xoffset += (maxAdvance - g.xadvance) / 2;
                g.xadvance = maxAdvance;
                g.kerning = null;
                g.fixedWidth = true;
            }
        }