Exports

TreeViz separates complete session exports from figure and data exports.

The Export button above the tree opens the Tree package panel. Its Images, Data, and Session sections group the download buttons. Export Session (JSON) is in the Session section. Downloads go to the location that the browser chooses. The panel closes after a successful export.

Session JSON

Use .treeviz.json when the output must preserve the full visualization:

• tree topology and branch lengths;
• metadata table and leaf binding;
• tracks and track order;
• view settings, layout, panel positions, and saved views;
• clade styles, selections, and annotations.

Session JSON is the exchange format between the browser, Python scripts, notebooks, and agents.

Figure formats

The Images section of the Export panel writes SVG, PNG, and PDF figures. Each image export is cropped to the visible content.

• SVG keeps text, paths, and shapes as editable vectors. Copy SVG puts the same SVG on the clipboard.
• PNG is a raster image. PNG options set the resolution to 72, 150, 300, or 600 DPI (default 300) and can make the background transparent.
• PDF keeps the vector figure on a page. PDF options set the page to Fit to tree (default, the page matches the cropped figure), Letter, or A4. Letter and A4 pages take Portrait or Landscape and center the figure on the page.

Include tracks (images) lists every visible metadata track. To leave a track out of SVG, PNG, and PDF exports, clear its checkbox. This setting does not change the session.

SVG export treats zoom the same way the screen does. Above zoom 1, text, strokes and node marks are scaled so the file matches the on-screen view. At zoom 1 and below, the SVG contains the unzoomed figure. When the in-figure legend is displayed, the export includes it, along with any hand-written legends.

From the browser API, await window.__treeviz.exportImage() returns a PNG or SVG data URL; see Export an image.

For automated rendering, inspect the output after the final layout change. Whitespace, clipped labels, or unreadable metadata tracks should be fixed in the layout before the figure is considered final.

Data formats

The Data section of the Export panel runs these commands. Each one returns { content, filename, mimeType } in ExecuteResult.value when called through window.__treeviz.execute.

Command	Output	Arguments
export.newick	Newick tree	none
export.nexus	Nexus tree	optional taxaBlock
export.leaf-names	leaf names under one clade as txt, csv, or tsv	stableKey, format, includeMetadata
export.metadata-tsv	current metadata table as TSV	none

For txt, export.leaf-names writes one name per line. For csv and tsv, it starts with a leaf_name header row, and includeMetadata: true adds the binding's row_key and confidence columns. The panel exports the whole tree. To export a single clade, use Export leaf names… in that clade's context menu.

Newick, Nexus, leaf-name, and metadata exports do not preserve the TreeViz visual state. Use .treeviz.json when visual state matters.

The CSV and TSV leaf-name exports and the metadata TSV export protect against spreadsheet formulas. When a cell begins with =, +, - or @, it gets a leading apostrophe, and spreadsheet apps show it as literal text. Leaf-name exports also guard a leading tab or carriage return, while the metadata TSV replaces tabs and line breaks inside cells with spaces. The leaf-name TSV export does the same, and the leaf-name CSV export quotes cells that contain commas, quotes, or line breaks. Numeric metadata values are written as they are. TXT leaf-name exports have no guard.

Python static export

The Python package can call a compatible external renderer. Neither the PyPI package nor this public repository installs one.

from treeviz import render_tree

render_tree(
    "(A,B,(C,D));",
    format="svg",
    output="tree.svg",
    command=["/path/to/treeviz-renderer"],
    width=1400,
    height=700,
    auto_crop=True,
    crop_padding=24,
    metrics="tree.metrics.json",
)

With auto_crop=True, exported SVG, PNG, and PDF artifacts are trimmed to their visible content. The metrics JSON records the content bounds, crop bounds, whitespace margins, fill ratios, and any crop warnings.

Without command, render_tree runs bun run treeviz render, which works only inside a TreeViz source checkout. output and metrics are resolved against the current working directory, not cwd, and the returned path is absolute. If the command cannot be started, render_tree raises FileNotFoundError. See Static export.