Font reference

Tetra bundles bitmap fonts sized for a 64 × 32 display. Choose a face based on how much text must fit, whether fixed-width glyphs matter, and which characters the app needs. render.Text uses tb-8 by default; set its font parameter to select another face.

Choose a font

This complete app accepts font and sample configuration values, which makes it useful for checking text before committing to a layout:

app.star

load("render.star", "render")

def main(config):
    font = config.str("font", "tb-8")
    sample = config.str("sample", "Aa09 ÑÖ")

    return render.Root(
        child = render.Box(
            width = 64,
            height = 32,
            child = render.Column(
                expanded = True,
                main_align = "center",
                cross_align = "center",
                children = [
                    render.Text(
                        sample,
                        font = font,
                        color = "#ffffff",
                    ),
                ],
            ),
        ),
    )

Use the smallest face that remains legible for the content:

• CG-pixel-3x5-mono and CG-pixel-4x5-mono maximize density.
• tom-thumb, tb-8, and 5x8 work well for compact labels and values.
• Dina_r400-6, 6x10, 6x10-rounded, and 6x13 improve readability when more vertical space is available.
• 10x20 is best for a short value or focal number.

Typography metrics

Bitmap fonts align glyphs around a common baseline. These measurements explain how much space each face needs and where its glyphs sit inside that space.

Baseline

The line on which most letters sit.

Ascent

The distance from the baseline to the font's highest point.

Cap height

The distance from the baseline to the top of a capital letter.

X-height

The height of a lowercase letter without an ascender.

Descent

The distance below the baseline reserved for descending glyphs.

Advance

The horizontal distance from one glyph's origin to the next.

render.Text positions a font on its baseline, offset upward by its descent. A cap height of 6 pixels with a 1-pixel descent is generally enough for readable upper- and lowercase Latin text. Accented Latin-1 characters such as Ñ, Ä, and Ö need additional ascent.

Available fonts

Every preview below was rendered by Tetra from the same sample app.

Preview	Font	Advance	Height	Cap height	Ascent	Descent	Notes
	tb-8	2–6	8	6	7	1	Default, variable-width face derived from 5x8. Digits use a fixed 5-pixel advance.
	Dina_r400-6	6	10	6	8	2	Jørgen Ibsen. Monospace Basic Latin and Latin-1.
	5x8	5	8	6	7	1	Markus Kuhn. Monospace with broad Latin coverage.
	6x13	6	13	9	11	2	Markus Kuhn. Taller monospace face with broad Unicode coverage.
	6x10	6	10	7	8	2	Olikraus. Medium monospace face for fixed-width layouts.
	6x10-rounded	6	10	7	8	2	Rounded 6x10 variant by Olikraus, modified by SynthSolar.
	10x20	10	20	13	16	4	Markus Kuhn. Large monospace face with broad Unicode coverage.
	tom-thumb	4	6	4	5	1	Robey Pointer. Tiny 4x6 monospace face with 3x5 usable glyph pixels.
	CG-pixel-3x5-mono	4	5	4	5	0	Ilmari Karonen. True 3x5 glyphs for the narrowest layouts.
	CG-pixel-4x5-mono	5	5	4	5	0	Ilmari Karonen. True 4x5 glyphs when one more pixel of width is available.

Compact numbers with tb-8

All tb-8 digits are 5 × 6 pixels and share the same advance. Set height = 6 and offset = -1 when a numeric row must fit tightly without cropping. The common +, -, /, *, =, %, and . symbols also fit; a comma extends into the 1-pixel descent and needs the full height.

app.star

load("render.star", "render")

def main(config):
    return render.Root(
        child = render.Box(
            width = 64,
            height = 32,
            child = render.Padding(
                pad = (4, 5, 4, 5),
                child = render.Column(
                    children = [
                        render.Text(
                            "COMPACT",
                            font = "CG-pixel-3x5-mono",
                            color = "#94a3b8",
                        ),
                        render.Box(width = 1, height = 4),
                        render.Text(
                            "123.45%",
                            font = "tb-8",
                            height = 6,
                            offset = -1,
                            color = "#22d3ee",
                        ),
                    ],
                ),
            ),
        ),
    )

Character coverage

Basic Latin covers ASCII letters, digits, punctuation, and common symbols. Latin-1 Supplement adds characters used by many Western European languages. Use a face with known Latin-1 support for names and locations, and preview the actual text when an app may receive characters beyond those ranges. Unsupported glyphs cannot be recovered by changing height or offset; select a font with the required coverage instead.