d2lang/d2 · error

expected "font-size" to be a number between 8 and 100

Error message

expected "font-size" to be a number between 8 and 100

What it means

D2 validates the "font-size" style by parsing it as an integer and requiring it to be between 8 and 100 inclusive. A value that is not an integer, or outside that range, returns this error and the style is rejected.

Source

Thrown at d2graph/d2graph.go:418

		if err != nil {
			return errors.New(`expected "multiple" to be true or false`)
		}
		s.Multiple.Value = value
	case "font":
		if s.Font == nil {
			break
		}
		if _, ok := d2fonts.D2_FONT_TO_FAMILY[strings.ToLower(value)]; !ok {
			return fmt.Errorf(`"%v" is not a valid font in our system`, value)
		}
		s.Font.Value = strings.ToLower(value)
	case "font-size":
		if s.FontSize == nil {
			break
		}
		f, err := strconv.Atoi(value)
		if err != nil || (f < 8 || f > 100) {
			return errors.New(`expected "font-size" to be a number between 8 and 100`)
		}
		s.FontSize.Value = value
	case "font-color":
		if s.FontColor == nil {
			break
		}
		if !color.ValidColor(value) {
			return errors.New(`expected "font-color" to be a valid named color ("orange"), a hex code ("#f0ff3a"), or a gradient ("linear-gradient(red, blue)")`)
		}
		s.FontColor.Value = value
	case "animated":
		if s.Animated == nil {
			break
		}
		_, err := strconv.ParseBool(value)
		if err != nil {
			return errors.New(`expected "animated" to be true or false`)
		}

View on GitHub (pinned to 0d69dca6f5)

Solutions

1. Use an integer between 8 and 100 (e.g. `x.font-size: 24`).
2. Remove units like "px" or "em" from the value.
3. Clamp generated values in code: if f < 8 { f = 8 }; if f > 100 { f = 100 }.
4. For larger text, use container/scale options instead of exceeding the font-size cap.

Example fix

// before (D2)
x: my shape
x.font-size: 150
// after
x: my shape
x.font-size: 100

func validFontSize(v string) (string, bool) {
	f, err := strconv.Atoi(v)
	if err != nil || f < 8 || f > 100 {
		return "", false
	}
	return v, true
}
// before applying: fs, ok := validFontSize(val); if !ok { fs = strconv.Itoa(clamp) }

func isFontSizeInRange(v string) bool {
	f, err := strconv.Atoi(v)
	return err == nil && f >= 8 && f <= 100
}

if err := obj.SetStyle("font-size", val); err != nil {
	if strings.Contains(err.Error(), `"font-size" to be a number between 8 and 100`) {
		// fallback to a safe default
		val = "16"
	}
}

When it happens

Trigger: Setting style key "font-size" to a non-integer string (e.g. "12.5", "big") or an integer below 8 or above 100 (e.g. `x.font-size: 150`).

Common situations: Users request large headline text beyond the cap (e.g. 200), use pixel units like "14px", or decimals like "12.5" copied from CSS.

Related errors

• expected "shadow" to be true or false
• expected "3d" to be true or false
• expected "multiple" to be true or false
• expected "font-color" to be a valid named color ("orange"),
• expected "animated" to be true or false

AI-assisted analysis of d2lang/d2@0d69dca6f5 (2026-08-31). Data as JSON: /api/errors/ae9536e98e623001. Report an issue: GitHub.