Glyph Contour Analyzer

A graphical tool for analyzing the contour structure of glyphs in TrueType/OpenType fonts. It extracts the outline curves of glyphs from a font file, performs geometric and topological analysis, and visualizes the results.

Features

Visualization

• Contour display: Draws the outer contours (solid blue lines) and inner contours (dashed red lines) of glyphs
• Optional vertex markers: Toggle the display of contour vertices
• Optional fill mode: Semi-transparent fill showing the solid area of glyphs
• Interactive navigation: Built-in matplotlib toolbar for pan/zoom

Analysis Functions

• Basic information: Number of contours, number of components, outer/inner contour counts, width and height of bounding box
• Geometric features: Area, perimeter, compactness, orientation (CW/CCW), vertex count for each contour
• Component structure: Groups contours into components (each outer contour plus its directly enclosed inner contours), identifying simple polygons vs. complex polygons with holes
• Contour topology: Nesting relationships between inner and outer contours
• Component topology: Nesting relationships between components (a glyph may contain multiple nested sub-components)

Interaction

• Input any Unicode character (e.g., Chinese characters, letters) to analyze
• Previous / Next glyph navigation through the font's glyph order
• Load any .ttf, .otf, or .ttc font file at runtime
• Toggles for outer contours, inner contours, vertices, and fill

Technical Stack

• Python 3
• Tkinter — graphical user interface (built into Python)
• matplotlib — glyph contour visualization
• fontTools — TrueType/OpenType font parsing and contour extraction
• NumPy — numerical computation (area, orientation, geometry)
• PrecisionPen — adaptive Bézier curve sampling for high-accuracy outline extraction

Installation

pip install matplotlib fonttools numpy

tkinter is included with standard Python distributions.

Usage

python GlyphTopos.py

Entry point:

• GlyphTopos.py — application entry point

1. The program launches with the default simkai.ttf in the project directory.
2. Enter any character (e.g., "国", "回", "A") in the input box and press Enter or click Analyze.
3. Use Previous / Next to browse glyphs in the font's internal order.
4. Use Browse... to load a different font file.
5. Use the checkboxes to toggle outer contours, inner contours, vertex points, and the transparent fill.
6. The right panel shows: basic info, per-contour geometric features, component structure, contour topology, and component topology.

Project Structure

/
├── GlyphTopos.py              Application entry point (matplotlib config + GUI launch)
├── glyph_analyzer/            Core analysis package
│   ├── __init__.py            Unified exports (PrecisionPen, GlyphAnalyzer, GlyphAnalyzerApp)
│   ├── pen.py                 PrecisionPen — adaptive Bézier curve sampling
│   ├── analyzer.py            GlyphAnalyzer — font loading, contour extraction, geometry & topology
│   └── gui/                   GUI sub-package
│       ├── __init__.py
│       ├── styles.py          ttk theme and style definitions
│       ├── toolbar.py         Top toolbar (font picker, character input, display toggles)
│       ├── panels.py          Outline plotting panel + data display panels
│       └── app.py             GlyphAnalyzerApp — main application class
├── simkai.ttf                 Example font file (Kai style)
└── README.md                  Documentation

Analysis Algorithm

1. Contour extraction — PrecisionPen adaptively samples each Bézier curve to form a high-precision polygon.
2. Type correction — Determines outer/inner contour types through the signed area and nesting depth of each polygon.
3. Component grouping — Groups each outer contour with the inner contours it directly encloses into one component; components whose outer contours are not enclosed by any other component are treated as independent.
4. Topology detection — Uses a ray-casting point-in-polygon test to determine nesting relationships, selecting the smallest enclosing contour (or component) as the direct parent.

License

Use for learning and research purposes.