Nib gives you access to the full set of SwiftUI system fonts, custom size and weight control, custom font files, and rich text with attributed strings.

System Fonts¶

System fonts are predefined on the Font class and match the macOS Dynamic Type styles:

import nib

nib.Text("Large Title", font=nib.Font.LARGE_TITLE)
nib.Text("Title", font=nib.Font.TITLE)
nib.Text("Title 2", font=nib.Font.TITLE2)
nib.Text("Title 3", font=nib.Font.TITLE3)
nib.Text("Headline", font=nib.Font.HEADLINE)
nib.Text("Subheadline", font=nib.Font.SUBHEADLINE)
nib.Text("Body", font=nib.Font.BODY)
nib.Text("Callout", font=nib.Font.CALLOUT)
nib.Text("Footnote", font=nib.Font.FOOTNOTE)
nib.Text("Caption", font=nib.Font.CAPTION)
nib.Text("Caption 2", font=nib.Font.CAPTION2)

Custom Size¶

Use Font.system() to create a system font with a specific point size and optional weight:

nib.Text("18pt Regular", font=nib.Font.system(18))
nib.Text("24pt Bold", font=nib.Font.system(24, nib.FontWeight.BOLD))
nib.Text("14pt Light", font=nib.Font.system(14, nib.FontWeight.LIGHT))

Font Weight¶

The FontWeight enum provides all standard weights:

You can also apply weight as a standalone modifier using font_weight:

nib.Text("Bold Body", font=nib.Font.BODY, font_weight=nib.FontWeight.BOLD)

Custom Fonts¶

Use Font.custom() to specify a font family by name. The font must be installed on the system or registered with the app.

nib.Text("Custom Font", font=nib.Font.custom("Inter", size=16))
nib.Text("Weighted", font=nib.Font.custom("Inter", size=16, weight=nib.FontWeight.SEMIBOLD))

Loading Custom Font Files¶

There are two ways to load custom font files (.ttf, .otf, .ttc):

1. Auto-detection from the assets/ directory (recommended)

Place font files anywhere inside your project's assets/ folder. Nib scans this directory on startup and registers every .ttf, .otf, .ttc, .woff, and .woff2 file it finds. The font name is derived from the filename without extension.

my_project/
  main.py
  assets/
    Inter-Regular.ttf
    Inter-Bold.ttf
    JetBrainsMono-Regular.ttf

# Fonts are auto-detected from assets/ -- no registration needed
nib.Text("Hello", font=nib.Font.custom("Inter-Regular", size=16))
nib.Text("Code", font=nib.Font.custom("JetBrainsMono-Regular", size=14))

2. Manual registration via app.fonts

For fonts stored elsewhere, register them by setting app.fonts to a dictionary mapping names to absolute file paths or URLs:

def main(app: nib.App):
    app.fonts = {
        "CustomFont": "/Users/me/fonts/CustomFont.ttf",
        "WebFont": "https://example.com/fonts/WebFont.otf",
    }

    app.build(
        nib.Text("Custom", font=nib.Font.custom("CustomFont", size=16))
    )

TextStyle¶

TextStyle groups font, decorations, and spacing into a single reusable object. Use it with the style parameter on Text.

nib.Text("Styled", style=nib.TextStyle(bold=True, italic=True, underline=True))

Available TextStyle attributes:

Combining decorations¶

# Bold, italic, and underlined
nib.Text(
    "Fancy Text",
    style=nib.TextStyle(
        font=nib.Font.system(18),
        bold=True,
        italic=True,
        underline=True,
        underline_color="blue",
        kerning=1.5,
    ),
)

Monospaced digits¶

Use monospaced_digit for numbers that need to align vertically (clocks, counters, tables):

nib.Text("12:34:56", style=nib.TextStyle(monospaced_digit=True, font=nib.Font.TITLE))

Predefined text styles¶

TextStyle also has predefined presets that mirror the system font hierarchy:

nib.Text("Title", style=nib.TextStyle.TITLE)
nib.Text("Headline", style=nib.TextStyle.HEADLINE)
nib.Text("Body", style=nib.TextStyle.BODY)
nib.Text("Caption", style=nib.TextStyle.CAPTION)

AttributedString -- Rich Text¶

AttributedString lets you combine multiple styles within a single Text view. Pass a list of attributed strings to the strings parameter:

nib.Text(
    strings=[
        nib.AttributedString("Bold", style=nib.TextStyle(bold=True)),
        nib.AttributedString(" Normal "),
        nib.AttributedString("Red", color="red"),
        nib.AttributedString(" Italic", style=nib.TextStyle(italic=True)),
    ],
)

Each AttributedString accepts:

Mixing fonts and colors¶

nib.Text(
    strings=[
        nib.AttributedString(
            "Important: ",
            style=nib.TextStyle(bold=True, color="red"),
        ),
        nib.AttributedString(
            "This is normal body text that follows the warning.",
            font=nib.Font.BODY,
        ),
    ],
)

Status line example¶

nib.Text(
    strings=[
        nib.AttributedString("Status: ", style=nib.TextStyle(bold=True)),
        nib.AttributedString("Connected", color="green"),
        nib.AttributedString(" | "),
        nib.AttributedString("3 devices", style=nib.TextStyle(monospaced_digit=True)),
    ],
)

Full Example¶

A complete app showcasing typography features:

import nib

def main(app: nib.App):
    app.title = "Typography"
    app.icon = nib.SFSymbol("textformat")
    app.width = 320
    app.height = 500

    app.build(
        nib.ScrollView(
            controls=[
                nib.VStack(
                    controls=[
                        # System font scale
                        nib.Text("System Fonts", font=nib.Font.HEADLINE),
                        nib.Text("Large Title", font=nib.Font.LARGE_TITLE),
                        nib.Text("Title", font=nib.Font.TITLE),
                        nib.Text("Headline", font=nib.Font.HEADLINE),
                        nib.Text("Body (default)", font=nib.Font.BODY),
                        nib.Text("Caption", font=nib.Font.CAPTION),

                        nib.Divider(),

                        # Weights
                        nib.Text("Font Weights", font=nib.Font.HEADLINE),
                        nib.Text("Ultra Light", font=nib.Font.system(16, nib.FontWeight.ULTRA_LIGHT)),
                        nib.Text("Light", font=nib.Font.system(16, nib.FontWeight.LIGHT)),
                        nib.Text("Regular", font=nib.Font.system(16, nib.FontWeight.REGULAR)),
                        nib.Text("Medium", font=nib.Font.system(16, nib.FontWeight.MEDIUM)),
                        nib.Text("Bold", font=nib.Font.system(16, nib.FontWeight.BOLD)),
                        nib.Text("Black", font=nib.Font.system(16, nib.FontWeight.BLACK)),

                        nib.Divider(),

                        # Text decorations
                        nib.Text("Text Styles", font=nib.Font.HEADLINE),
                        nib.Text("Bold", style=nib.TextStyle(bold=True)),
                        nib.Text("Italic", style=nib.TextStyle(italic=True)),
                        nib.Text("Underline", style=nib.TextStyle(underline=True)),
                        nib.Text("Strikethrough", style=nib.TextStyle(strikethrough=True)),
                        nib.Text("Monospaced", style=nib.TextStyle(monospaced=True)),

                        nib.Divider(),

                        # Attributed string
                        nib.Text("Rich Text", font=nib.Font.HEADLINE),
                        nib.Text(
                            strings=[
                                nib.AttributedString("Hello ", color="blue"),
                                nib.AttributedString("World", style=nib.TextStyle(bold=True, color="red")),
                                nib.AttributedString("!", font=nib.Font.TITLE),
                            ],
                        ),
                    ],
                    spacing=6,
                    alignment=nib.HorizontalAlignment.LEADING,
                    padding=16,
                ),
            ],
        )
    )

nib.run(main)