SVG Font Format

SVG fonts are an XML-based font format defined in the SVG 1.1 specification, where each glyph is represented as an SVG path or shape. Introduced in 2001 as part of the broader Scalable Vector Graphics standard, SVG fonts were designed to enable custom typography on the web before more sophisticated font formats like WOFF became available.

Brief History

SVG fonts emerged during the early web era when designers had limited options for custom typography. The format was part of the W3C's vision for rich, scalable graphics on the web:

• 2001: SVG 1.1 specification released, including font module
• 2009-2011: Early web font adoption, including SVG fonts in Safari/iOS
• 2012: Chrome/Firefox begin deprecation in favor of WOFF
• 2016-2017: Most browsers remove SVG font support
• Present: Only Safari maintains legacy support; format considered obsolete

Core Characteristics

SVG fonts are fundamentally different from traditional font formats:

• Glyphs defined as SVG paths in XML format
• Can include colors, gradients, and effects (unique at the time)
• No hinting mechanism for low-resolution rendering
• Limited typography features compared to OpenType
• Large file sizes due to verbose XML structure
• Poor rendering performance compared to binary font formats

While SVG fonts offered some unique capabilities like native color support, their limitations and the emergence of better alternatives led to widespread deprecation. Today, OpenType color fonts (COLR/CPAL, SVG table) and WOFF2 provide superior solutions for web typography.

The story of SVG fonts is a cautionary tale about premature standardization and the challenges of balancing innovation with practicality. While the format introduced novel capabilities, fundamental design flaws and competition from better alternatives led to one of the web's fastest format deprecations.

The Pre-Web Font Era (1990s-2008)

Before widespread web font support, designers faced severe typographic constraints:

Various solutions were attempted in the late 1990s and early 2000s, including TrueDoc, Embedded OpenType (EOT), and JavaScript font replacement techniques, but none achieved widespread adoption due to licensing issues, browser support problems, or technical limitations.

SVG 1.1 and Font Module (2001-2003)

When the W3C developed the SVG 1.1 specification, they included a font module with ambitious goals:

• XML-based: Fonts defined in human-readable, editable XML
• Vector graphics integration: Seamless use of SVG paths for glyphs
• Color and effects: Native support for fills, strokes, gradients, and filters
• Web-native: No need for binary formats or proprietary technologies
• Scriptable: Could be manipulated via JavaScript and DOM APIs

The SVG font specification was published in September 2001 as part of SVG 1.1, and it represented a genuinely novel approach to web typography. However, implementation was slow and inconsistent.

Early Implementation and Challenges (2003-2009)

Browser vendors struggled with SVG font implementation:

*Safari and iOS still support SVG fonts for backward compatibility, but Apple recommends using modern font formats.

Technical Problems Emerge (2009-2012)

As web fonts gained traction, fundamental flaws in the SVG font format became apparent:

The Web Font Revolution and WOFF (2009-2012)

While SVG fonts struggled, a better solution emerged:

• 2009: @font-face CSS support arrives in Firefox 3.5 and Safari 3.1
• 2010: Google Fonts launches with TTF/WOFF fonts, making custom typography accessible
• 2010: WOFF 1.0 specification published, providing compressed wrapper for TrueType/OpenType
• 2011: All major browsers (except IE8) support WOFF
• 2012: Industry consensus shifts decisively toward WOFF as the standard web font format

WOFF offered everything SVG fonts couldn't: compact size, fast rendering, full OpenType feature support, excellent hinting, and universal browser adoption. The format wars were over before they really began.

Deprecation and Removal (2012-2017)

Browser vendors moved quickly to deprecate SVG fonts:

By 2017, SVG fonts were effectively dead for new projects. Only Safari/iOS maintained support, and even Apple's developer documentation recommended against using the format.

The Color Font Solution (2016-Present)

Ironically, SVG fonts' main advantage—color support—eventually returned in a better form:

• COLR/CPAL tables: OpenType color fonts using layered vector glyphs
• SVG table: OpenType fonts can embed SVG graphics per glyph (different from SVG fonts)
• COLR v1: Gradients, transformations, and advanced graphics in color fonts
• Emoji fonts: Color emoji using OpenType color technologies

These modern solutions provide everything SVG fonts offered (color, gradients, effects) while maintaining the performance, features, and compatibility of standard font formats.

Current Status and Legacy (2025)

Today, SVG fonts exist only as:

• Safari legacy support: Maintained for backward compatibility but not recommended
• Historical artifacts: Old web projects and archived sites
• Educational examples: Demonstrating early web font attempts
• Cautionary tale: Example of premature standardization

For any current project, SVG fonts should be converted to WOFF2 or modern OpenType formats. The format's brief moment in web history is over, but its influence on color font development and web typography evolution remains significant.

SVG fonts use XML to define font data, making them fundamentally different from binary font formats. While this approach offered some advantages, it came with significant performance and file size penalties.

Format Structure

SVG fonts are defined within SVG documents using specific XML elements:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" 
  "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg">
  <defs>
    <font id="MyFont" horiz-adv-x="500">
      <font-face font-family="MyFont" units-per-em="1000" 
                 ascent="800" descent="200"/>
      <missing-glyph horiz-adv-x="500" 
                     d="M50 0 L50 700 L450 700 L450 0 Z"/>
      <glyph unicode="A" horiz-adv-x="600" 
             d="M100 0 L250 700 L350 700 L500 0 L400 0 
                L350 200 L250 200 L200 0 Z"/>
      <!-- More glyphs... -->
    </font>
  </defs>
</svg>

Key Elements

Glyph Path Data

Glyphs in SVG fonts use the same path syntax as regular SVG graphics:

Color Support

SVG fonts could include colors and effects using standard SVG attributes:

<glyph unicode="★" horiz-adv-x="500">
  <path d="M250 400 L280 300 L380 300 L300 240 
           L330 140 L250 200 L170 140 L200 240 
           L120 300 L220 300 Z" 
        fill="#FFD700" stroke="#FFA500" stroke-width="5"/>
</glyph>

While color support was novel, most browsers rendered SVG fonts in monochrome, defeating one of the format's key advantages.

SVG fonts follow a hierarchical XML structure that differs significantly from binary font formats.

Complete Font Example

<?xml version="1.0" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg">
  <defs>
    <font id="ExampleFont" horiz-adv-x="500">
      <!-- Font Metadata -->
      <font-face 
        font-family="Example Font"
        font-weight="400"
        font-style="normal"
        units-per-em="1000"
        ascent="800"
        descent="200"
        x-height="450"
        cap-height="700"/>
      
      <!-- Missing Glyph (fallback) -->
      <missing-glyph horiz-adv-x="500">
        <path d="M50 0 L50 700 L450 700 L450 0 Z"/>
      </missing-glyph>
      
      <!-- Glyphs -->
      <glyph unicode="A" horiz-adv-x="600"
        glyph-name="A"
        d="M100 0 L250 700 L350 700 L500 0 L400 0 
           L350 200 L250 200 L200 0 Z"/>
      
      <glyph unicode="B" horiz-adv-x="550"
        glyph-name="B"
        d="M100 0 L100 700 L300 700 Q400 700 450 650 
           Q500 600 500 500 Q500 420 460 380 
           Q500 340 500 260 Q500 150 450 75 
           Q400 0 300 0 Z"/>
      
      <!-- Kerning -->
      <hkern u1="A" u2="V" k="-50"/>
      <hkern u1="V" u2="A" k="-50"/>
    </font>
  </defs>
</svg>

Embedding in Web Pages

SVG fonts could be used via CSS @font-face (in supporting browsers):

/* Historical example - no longer works in most browsers */
@font-face {
  font-family: 'ExampleFont';
  src: url('example.svg#ExampleFont') format('svg');
}

body {
  font-family: 'ExampleFont', sans-serif;
}

SVG fonts had some unique capabilities but were severely limited compared to modern font formats.

Unique Capabilities

Major Limitations

• No hinting: Terrible rendering at small sizes
• Basic kerning only: Simple horizontal kerning pairs, no contextual positioning
• No OpenType features: No ligatures, alternates, small caps, etc.
• Performance issues: XML parsing overhead for every glyph
• Large file sizes: 5-10x larger than binary formats
• Poor complex script support: No proper shaping for Arabic, Devanagari, etc.
• Limited browser support: Never achieved universal compatibility

Historical Usage (2009-2013)

SVG fonts saw limited use during the early web font era:

• Early iPhone web apps (before App Store)
• Safari-only websites and web applications
• Icon fonts (before icon fonts became widespread)
• Experimental typography projects
• Mobile-first websites targeting iOS

Modern Reality (2025)

SVG fonts should never be used in new projects:

• Use WOFF2: For all web typography needs
• Use OpenType color fonts: For color/gradient typography
• Use SVG graphics: For icons and illustrations (not as fonts)
• Convert legacy SVG fonts: To TTF/OTF/WOFF2 if encountered

When You Might Encounter SVG Fonts

• Maintaining legacy websites from 2009-2013 era
• Archived web projects or historical sites
• Old iOS web app projects
• Early icon font libraries
• Web typography experiments and tech demos

SVG fonts compare poorly to all modern alternatives:

Color Fonts: Modern Alternative

For color typography (SVG fonts' main selling point), use modern solutions:

• OpenType COLR/CPAL: Layered color glyphs, excellent browser support
• OpenType SVG table: Embed SVG per glyph (different from SVG fonts)
• COLR v1: Gradients and advanced graphics in color fonts
• Emoji fonts: Standardized color emoji using OpenType

Converting SVG Fonts to Modern Formats

If you encounter SVG fonts in legacy projects, convert them immediately:

# Using FontForge (command line)
fontforge -c 'Open("font.svg"); Generate("font.ttf")'

# Then convert to WOFF2 for web
woff2_compress font.ttf

# Or use online tools like FontSquirrel Generator
# Upload SVG, download WOFF2/WOFF/TTF package

Updating CSS

Replace old SVG font references:

@font-face {
  font-family: 'MyFont';
  src: url('myfont.svg#MyFont') format('svg');
}

@font-face {
  font-family: 'MyFont';
  src: url('myfont.woff2') format('woff2'),
       url('myfont.woff') format('woff');
  font-display: swap;
}

Tools for SVG Font Conversion

• FontForge: Free, open-source font editor
• Font Squirrel Generator: Web-based conversion (deprecated SVG support)
• Font Converter Tool: Our online converter
• Transfonter: Online font converter

Creating SVG Fonts (Not Recommended)

For historical reference only—do not create new SVG fonts:

• Early tools: Inkscape, Batik, custom scripts
• Manual XML editing (extremely tedious)
• FontForge can export to SVG font format
• Modern approach: Create OTF/TTF fonts instead