Static Export (SVG, PNG, PDF)

JSXGraph.jl supports exporting boards as static images via save() or the direct export functions save_svg(), save_png(), save_pdf().

Requirements

Static export is provided via a package extension that depends on NodeJS_22_jll. Node.js v22 is automatically downloaded as a Julia artifact — no system installation needed. On first export, required npm packages are installed in a package-local directory (.node_deps/).

Format	npm packages (auto-installed)
SVG	`jsdom`
PNG	`jsdom`, `sharp`
PDF	`jsdom`, `pdfkit`, `svg-to-pdfkit`

using Pkg
Pkg.add("NodeJS_22_jll")

Usage

Export via `save()`

Load NodeJS_22_jll, then the save() function dispatches on the file extension:

using JSXGraph
using NodeJS_22_jll  # activates static export extension

b = board("myboard", xlim=(-5, 5), ylim=(-5, 5)) do b
    push!(b, point(1, 2; name="A"))
    push!(b, circle(point(0, 0), 3; strokeColor="blue"))
end

# HTML export (always available)
save("plot.html", b)

# SVG export
save("plot.svg", b)

# PNG export
save("plot.png", b)

# PNG with 2× resolution (Retina/HiDPI)
save("plot_hd.png", b; scale=2)

# PDF export
save("plot.pdf", b)

Direct export functions

save_svg("plot.svg", b)
save_png("plot.png", b)
save_png("plot_hd.png", b; scale=2)
save_pdf("plot.pdf", b)

Supported Formats

Extension	Format	Backend
`.html`	Self-contained HTML page	Built-in
`.svg`	Scalable Vector Graphics	NodeJS22jll + jsdom
`.png`	Portable Network Graphics	NodeJS22jll + jsdom + sharp
`.pdf`	PDF document	NodeJS22jll + jsdom + pdfkit + svg-to-pdfkit

Unsupported extensions (e.g. .gif, .bmp) raise an ErrorException.

Scale Factor (PNG)

The scale keyword controls the output resolution for PNG exports:

save("plot.png", board; scale=1)  # native resolution (e.g. 500×500)
save("plot.png", board; scale=2)  # 2× resolution (e.g. 1000×1000)
save("plot.png", board; scale=3)  # 3× resolution (e.g. 1500×1500)

Higher scale values produce sharper images suitable for print or HiDPI displays.

API Reference

JSXGraph.save_svg — Function

save_svg(filename::String, board::Board)

Export a board as a static SVG image file.

Requires NodeJS_22_jll to be installed. Add it with:

using Pkg; Pkg.add("NodeJS_22_jll")

Then load it before calling save_svg:

using NodeJS_22_jll
save("plot.svg", board)

Arguments

filename::String: Output file path (should end in .svg)
board::Board: The board to export

source

JSXGraph.save_png — Function

save_png(filename::String, board::Board; scale::Int=1)

Export a board as a PNG image file.

The scale parameter controls the resolution multiplier (e.g. scale=2 produces a 2× resolution image suitable for Retina/HiDPI displays).

Requires NodeJS_22_jll to be installed. Add it with:

using Pkg; Pkg.add("NodeJS_22_jll")

Then load it before calling save_png:

using NodeJS_22_jll
save("plot.png", board)
save("plot_hd.png", board; scale=2)  # 2× resolution

Arguments

filename::String: Output file path (should end in .png)
board::Board: The board to export
scale::Int=1: Resolution multiplier (1 = native, 2 = 2× Retina)

source

JSXGraph.save_pdf — Function

save_pdf(filename::String, board::Board)

Export a board as a PDF document.

Requires NodeJS_22_jll to be installed. Add it with:

using Pkg; Pkg.add("NodeJS_22_jll")

Then load it before calling save_pdf:

using NodeJS_22_jll
save("plot.pdf", board)

Arguments

filename::String: Output file path (should end in .pdf)
board::Board: The board to export

source

How It Works

A Node.js script is generated that creates a virtual DOM using jsdom
The JSXGraph library is injected into the virtual DOM
The board is initialized with all elements
The SVG element is extracted from the DOM
For SVG: the raw SVG is written with proper XML headers
For PNG: sharp converts the SVG to a raster image at the specified scale
For PDF: pdfkit + svg-to-pdfkit embed the SVG in a PDF document

Node.js is provided by NodeJS_22_jll (Julia artifact, no system dependency).

Troubleshooting

"SVG/PNG/PDF export requires the NodeJS22jll package": Load it first:

using NodeJS_22_jll

npm package installation fails: Try installing manually:

cd ~/.julia/packages/JSXGraph/<hash>/.node_deps
~/.julia/artifacts/<nodejs_hash>/bin/npm install jsdom sharp pdfkit svg-to-pdfkit