VSDX → HTML Converter

Convert Microsoft Visio files (.vsdx) to interactive, standalone HTML — no Visio license or internet connection required.

Getting started after clone

# 1. Install the vsdx library (not on PyPI — install from GitHub)
pip3 install git+https://github.com/dave-howard/vsdx.git
# 2. Install the converter as a local editable package
pip3 install -e .# 3. Convert a file
convert diagram.vsdx

Usage

convert diagram.vsdx # → diagram.html (same directory)
convert diagram.vsdx -o output.html # custom output path
convert diagram.vsdx --theme corporate # with theme
convert *.vsdx # batch conversion
convert --list-themes # show available themes
convert --version # show version

Available themes

Theme	Description
default	Preserves Visio colors
corporate	Professional dark tones with subtle shadows
modern	Minimalist pastels with rounded corners

Testing

Generate test files and run the test suite:

python3 tests/create_test_vsdx.py # generate test .vsdx files (run once)
python3 -m pytest tests/test_converter.py -v

The test files are excluded from version control (.gitignore), so create_test_vsdx.py must be run after each fresh clone.

Test coverage

Class	What is tested
TestParser	Parsing nodes, edges, coordinates, text, multi-page, empty pages, error handling
TestRenderer	HTML output, SVG content, themes, tab navigation, auto-fit JS, orthogonal paths
TestThemes	Theme lookup, required fields, color override flags

Architecture

.vsdx → parser → JSON graph → renderer → .html

Layer	File	Responsibility
Parser	parser/vsdx_parser.py	Reads .vsdx (ZIP+XML), extracts shapes, connectors, and pages
Intermediate	JSON dict	Provider-agnostic graph format (nodes + edges per page)
Renderer	renderer/svg.py	Generates inline SVG in a standalone HTML file
Themes	themes.py	Style presets that override Visio colors

Known limitations

• Legacy .vsd format — binary .vsd files are not supported; open in Visio and save as .vsdx first
• Master shape style inheritance — complex style inheritance from Visio master pages may differ from the original Visio rendering
• No cross-diagram navigation — links between connected diagrams are not supported out of the box
• Zoom/pan — simpler than dedicated diagram viewers such as draw.io