Troubleshooting Glyph Viewer: Common Issues and Fixes

Glyph Viewer: A Complete Guide for Designers and Typographers

Introduction

A glyph viewer is an essential tool for anyone working with type — from type designers to UI designers, brand teams, and typographers. It lets you inspect individual glyphs, test OpenType features, compare character sets, and verify spacing and kerning. This guide explains what glyph viewers do, when to use them, common features, workflows for design and QA, and recommended tools.

What a glyph viewer does

• Displays glyphs: Shows every glyph in a font, including alternate forms, ligatures, and production glyphs (e.g., discretionary ligatures).
• Maps Unicode/code points: Reveals the Unicode code point and glyph name for each character.
• Inspects metrics: Shows advance width, left/right sidebearings, bounding boxes, and glyph outlines.
• Tests OpenType features: Enables features like ligatures, contextual alternates, positional forms, kerning, and stylistic sets.
• Exports and compares: Exports glyphs or PDFs, and compares glyphs across fonts for visual differences.

When designers and typographers use a glyph viewer

• Designing new typefaces: Inspect outlines, anchor points, and interpolation families.
• Quality assurance: Verify kerning pairs, missing glyphs, and Unicode mappings before release.
• Localization checks: Ensure diacritics and language-specific glyphs are present and correctly positioned.
• UI/UX and icon fonts: Confirm glyphs map to correct code points and don’t conflict with system symbols.
• Accessibility: Verify fallback glyphs, private-use-area mappings, and symbol sets.

Key features to look for

• Glyph grid and search: Fast scanning and lookup by name or code point.
• Outline and point editing preview: View contours, handles, and control points.
• Metrics inspector: Measure bounding boxes, sidebearings, and advance width numerically.
• OT feature toggles: Toggle kerning, liga, calt, and other features with live preview.
• Text sample rendering: Render sample text at various sizes and hinting settings.
• Glyph comparison: Side-by-side comparison across fonts or glyphs.
• Export options: SVG, PNG, PDF, or direct copy to clipboard.
• Batch operations: Rename glyphs, remap code points, or export subsets.

Typical workflows

Designing glyphs

1. Open your working font in the glyph viewer.
2. Inspect problem glyphs in outline mode; check node placement and curve direction.
3. Toggle interpolation or masters (if supported) to confirm smooth transitions.
4. Test kerning pairs and contextual alternates in sample text.
5. Export target glyphs as SVG for client review or web use.

QA before release

1. Run a glyph grid scan for missing Unicode blocks relevant to target languages.
2. Use search to find duplicates or unintended .null/empty glyphs.
3. Test OpenType features and run through common pangrams and locale-specific sample text.
4. Check weight and width consistency across families.
5. Export a character map and metrics report for documentation.

Localization check

1. Identify required language subsets (e.g., Latin Extended, Cyrillic).
2. Filter glyph grid to those ranges and inspect diacritic positioning.
3. Test combining marks in sample strings to ensure correct attachment and fallback behavior.

Tips and best practices

• Use representative sample text: For UI fonts, include numerals, punctuation, and common ligatures.
• Check small sizes: Hinting matters—preview at target sizes to spot legibility issues.
• Verify mapping for icons: Confirm icon fonts use private-use code points and include documentation for implementers.
• Automate checks: Use scripts or batch exports when working with large families or multiple weights.
• Keep naming consistent: Follow standard glyph naming (Adobe/TTX conventions) to avoid interoperability issues.

Recommended tools

• FontForge — free, open-source editor and viewer with extensive feature set.
• Glyphs — macOS-focused type design app with a built-in viewer and OT feature testing.
• RoboFont — UFO-based editor popular with type designers who script workflows.
• Typelight / FontView (platform-specific viewers) — quick inspection utilities.
• Online viewers — simple glyph inspection without installing software (good for quick checks).

Quick reference checklist before releasing a font

• All required Unicode ranges covered
• No empty or malformed glyphs
• Kerning and OT features functioning
• Consistent metrics across weights
• Proper hinting for target sizes
• Exported files include correct metadata and naming

Conclusion

A glyph viewer is more than a convenience—it’s a core part of font production, QA, and implementation. Mastering its features speeds up design iterations, avoids costly mistakes, and ensures fonts behave predictably across platforms and languages. Use the workflows and checklist above to integrate glyph inspection into your regular process.