SVG in.Pixels out.

A header-only C++17 library that parses, queries, restyles and rasterizes SVG. Use it from C++ and Python, or the shell.

Get started API reference

$pip install novasvg

An eight-point star with a blue to magenta gradient, glowing, inside a dotted orbit ring. Rendered by NovaSVG from the SVG shown on the left. — rendered by NovaSVG

star.svg

<svg viewBox="0 0 240 240" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <linearGradient id="nova" x1="0" y1="0" x2="1" y2="1">
      <stop offset="0" stop-color="#1867b2"/>
      <stop offset="1" stop-color="#b6489b"/>
    </linearGradient>
    <filter id="glow"><feGaussianBlur stdDeviation="9"/></filter>
  </defs>
  <circle class="orbit" cx="120" cy="120" r="108" fill="none" stroke="url(#nova)"
          stroke-width="2" stroke-dasharray="2 7" stroke-linecap="round"/>
  <circle cx="120" cy="120" r="58" fill="url(#nova)" opacity=".55" filter="url(#glow)"/>
  <path class="star" fill="url(#nova)" d="M120 36 L133 89 L179 61 L151 107 L204 120 L151 133 L179 179 L133 151 L120 204 L107 151 L61 179 L89 133 L36 120 L89 107 L61 61 L107 89Z"/>
  <circle cx="120" cy="120" r="9" fill="#fff" opacity=".92"/>
</svg>

Real renders, straight from NovaSVG

Every image here was drawn by NovaSVG from the files in the repository's data folder. Gradients, filters, text and Mermaid diagrams all go through the same renderer.

A roaring tiger head drawn with hundreds of paths — **Tiger**`tiger.svg`

A Mermaid sankey diagram of energy flows — **Sankey diagram**`mermaid`

A Venn diagram of three overlapping teams — **Venn diagram**`mermaid`

An architecture diagram with a server, a database and two storage nodes — **Architecture**`mermaid`

A gradient filled rectangle next to a blurred radial gradient ellipse — **Gradients and blur**`feature-gradient-filter.svg`

A Mermaid pie chart comparing rendering backends — **Pie chart**`mermaid`

Restyle an SVG without editing it

Apply a stylesheet when you load the document. The same file renders in a new palette and the original stays untouched. Find elements first with query_selector_all, CSS selectors included.

python

import novasvg

doc = novasvg.Document.load_from_file("star.svg")

# find things with CSS selectors
stars = doc.query_selector_all("path.star")

# restyle, then render with a transparent background
doc.apply_stylesheet(".star { fill: #ffb02e } .orbit { stroke: #ffb02e }")
doc.render_to_bitmap(720, 720, 0).write_to_png("star-gold.png")

The star with its original blue to magenta gradient

Original With stylesheet

Install it, render something

Pick a language once. The install and example panels both follow your choice.

Install

Option 1 — pip (recommended)

bash

pip install novasvg

The Python package ships a pre-built novasvg binary alongside the Python extension. After install, the novasvg command is available directly in your shell — no compiler or CMake needed.

Option 2 — build & install with CMake

bash

git clone https://github.com/MohammadRaziei/novasvg.git
cd novasvg
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j$(nproc)

# Install to system (adds `novasvg` to PATH)
sudo cmake --install build

Requires CMake 3.19+ and a C++17 compiler. Builds the binary from source — useful if you want a custom build configuration or are on a platform without a pre-built wheel.

CMake — FetchContent

# CMakeLists.txt
include(FetchContent)
FetchContent_Declare(
  novasvg
  GIT_REPOSITORY https://github.com/MohammadRaziei/novasvg.git
  GIT_TAG        master
)
FetchContent_MakeAvailable(novasvg)

# Link the header-only target
target_link_libraries(my_app PRIVATE novasvg::novasvg)

Requires CMake 3.19+ and a C++17-compatible compiler. Link against novasvg::novasvg and include <novasvg/novasvg.h>. The library is header-only, so there is nothing to compile separately. You can also copy include/novasvg/ into your project, or use the single-header novasvg.h from the latest release.

bash

pip install novasvg

Requires Python 3.9+ and NumPy. Wheels ship a pre-built native extension for Linux, macOS, and Windows.
Install the latest development build directly from source: pip install git+https://github.com/MohammadRaziei/novasvg

Example

bash

# SVG -> PNG (writes input.png next to the input)
novasvg input.svg

# Choose the output file and size
novasvg input.svg -o output.png -w 800 -H 600

# Apply CSS, inspect, query and batch-convert
novasvg input.svg --style "rect { fill: red; }"
novasvg info image.svg --json
novasvg query "circle" input.svg
novasvg batch ./svgs ./images

c++

#include <novasvg/novasvg.h>
#include <iostream>

int main() {
    // Load an SVG document from a file
    auto doc = novasvg::Document::loadFromFile("artwork.svg");
    if (!doc) return 1;

    // Render to a bitmap (auto-sized) and save it as PNG
    auto bitmap = doc->renderToBitmap();
    bitmap.writeToPng("artwork.png");

    // Query elements with CSS selectors
    auto rectangles = doc->querySelectorAll("rect");
    std::cout << "Found " << rectangles.size() << " rectangles\n";

    // Document dimensions
    std::cout << "Size: " << doc->width() << "x" << doc->height() << "\n";
    return 0;
}

python

import novasvg

# One-liner: SVG file -> PNG file
novasvg.svg2png("input.svg", "output.png", width=800)

# Or work with the document model
doc = novasvg.Document.load_from_file("artwork.svg")
print(doc.width, doc.height)

# Query elements with CSS selectors and restyle the document
rects = doc.query_selector_all("rect")
doc.apply_stylesheet("rect { fill: red; }")

# Render to a bitmap, save it, or get the pixels as a NumPy array
bitmap = doc.render_to_bitmap(400, 300)
bitmap.write_to_png("artwork.png")
pixels = bitmap.numpy()   # shape (300, 400, 4)

Accuracy

Mean RMSE against a Chromium render. Lower is closer.

Speed

Average render time per sample. Lower is faster.

Open the full report

API reference

Full references for the C++ library, the Python binding and the command-line tool.

CLI Reference v0.10.0

Command-line tool for converting SVG to PNG, inspecting documents, querying elements with CSS selectors and converting whole directories. Covers all options and subcommands including --width, --scale, --background-color, --css-file, info, query and batch.

Written in Markdown

Open CLI Reference

C++ API C++17

Header-only C++17 API with RAII semantics. Covers novasvg::Document, novasvg::Element, novasvg::Bitmap, novasvg::Matrix, novasvg::Box and novasvg::Color: loading from files, strings or memory, CSS selector queries, stylesheets, transforms, font management and rasterization to bitmaps or PNG.

Generated with Doxygen

Open C++ Reference

Python API Python 3.9+

nanobind-based extension module. Documents Document, Element, Node, Bitmap, Matrix, Box and Color, the svg2png helper, the novasvg.fonts submodule, and the bundled command-line tool. Rendered pixels are available as NumPy arrays. Ships pre-built wheels for Linux, macOS, and Windows.

Generated with Sphinx

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