Custom Fonts

Ogre supports multiple font loading strategies. It ships with built-in Go fonts that work out of the box.

Built-in fonts

Ogre loads Go’s default fonts on startup. These render immediately with no configuration.

Google Fonts

When Ogre encounters a font-family in your HTML that it doesn’t recognize, it automatically fetches it from Google Fonts. Both regular (400) and bold (700) weights are loaded.

<div style="font-family: Roboto; font-size: 48px; color: white">
  This text uses Roboto from Google Fonts
</div>

Fetched fonts are cached on disk in a temporary directory.

Loading fonts from files

fontData, _ := os.ReadFile("Inter-Regular.ttf")

result, _ := ogre.Render(html, ogre.Options{
    Fonts: []ogre.FontSource{{
        Name:   "Inter",
        Weight: 400,
        Style:  "normal",
        Data:   fontData,
    }},
})

Loading fonts from URLs

result, _ := ogre.Render(html, ogre.Options{
    Fonts: []ogre.FontSource{{
        Name:   "Inter",
        Weight: 400,
        Style:  "normal",
        URL:    "https://example.com/Inter-Regular.ttf",
    }},
})

URL fonts are fetched and cached automatically.

Pre-loading fonts on a shared renderer

r := ogre.NewRenderer()

r.LoadFont(ogre.FontSource{
    Name:   "Inter",
    Weight: 400,
    Style:  "normal",
    Data:   regularData,
})
r.LoadFont(ogre.FontSource{
    Name:   "Inter",
    Weight: 700,
    Style:  "normal",
    Data:   boldData,
})

// All subsequent renders use these fonts
result, _ := r.Render(html, ogre.Options{Width: 1200, Height: 630})

Supported formats

• TTF (TrueType)
• OTF (OpenType)
• WOFF (Web Open Font Format, automatically decompressed)

WOFF2 is not supported. Convert WOFF2 fonts to TTF or OTF before loading them.

Font rendering

In SVG output, font glyphs are converted to path data. This makes SVGs self-contained — they render correctly without the font installed. In PNG/JPEG output, fonts are rasterized directly.