MatPlotLibNet — matplotlib for .NET

MatPlotLibNet is a charting library for C#, .NET 10 and .NET 8, inspired by matplotlib. It draws 83 chart types and saves them as SVG, PNG, PDF or an animated GIF, straight from your server code. It does not need a JavaScript framework, a WebView or a hosted service.

It has a fluent API and it works with dependency injection. It ships with 148 colormaps, 30 themes, 13 map projections with embedded Natural Earth data, LaTeX-style MathText, text in any script, O(1) streaming with 53 technical indicators, a control room (Plt.OpsDashboard() — KPI tiles, state timelines, one shared trend window), and an MCP server so an AI agent can draw with it. Charts render natively in Blazor, WPF, MAUI, Avalonia, Uno and ASP.NET Core, inside a Verso notebook cell, and TypeScript clients are there for Angular, React and Vue.

Where this is going

1.18 draws charts inside a Verso notebook. Verso is the open-source notebook built to replace Polyglot Notebooks, and MatPlotLibNet.Verso is an extension you install from its Extensions panel. After that a cell that ends on a figure — or on the builder that makes one, without .Build() — shows the chart instead of a line of type names. The chart fills the width of the cell, and one taller than the cell can show gets a scroll box rather than being squeezed into a size nobody chose. The package carries the extension and nothing else on purpose: a notebook loads an extension in its own context, so a second copy of the charting library shipped alongside would be a different Figure from the one the cell made. MatPlotLibNet.Notebooks stands still at the version it reached; the runtime under Polyglot Notebooks has ended, and notebook work belongs in Verso now.

1.17.1 is a patch on top of it. A clicked data point now reaches your own code — the desktop controls and the SignalR route both hand it over with its series, its value and where it was. The control room gained a service-topology panel, GroupedBar draws several bars per category in one call, DensityScatter colours a scatter by how crowded it is, and three accessible colour sequences arrived (petroff6, petroff8, petroff10). All fourteen packages carry an icon and release notes now, and the documentation site has a page that translates matplotlib into C#, call by call.

1.17 draws text in any script. Arabic letters join, Hebrew reads right to left, and a number or a Latin word inside Arabic or Hebrew text is placed in the correct position, using the font that ships in the package. The Unicode bidi algorithm is implemented in full and checked against Unicode's own 861,948 test cases; HarfBuzz shapes each run. Other scripts need a font file: SkiaFonts.Register(path) registers one, and the MCP server reads font files from the MATPLOTLIBNET_FONTS variable. Latin text is now kerned too, so text widths changed by up to 2 px per letter pair.

1.16 adds a data table beside every chart, for a reader who cannot see the picture. figure.ToDataTables() returns the figure's data as tables with typed columns, and you can write each table as HTML, Markdown or CSV. Every host serves the table: an ASP.NET Core endpoint next to the SVG endpoint, a ShowDataTable option on the Blazor component, a chartDataTable field in the GraphQL schema, and a fifth MCP tool. The same release fixed the streaming series. A point and a candle are now stored as one value, so a snapshot can no longer show a point or a bar that never existed. The buffer behind them is now the generic RingBuffer<T>.

1.15 added support for AI agents. MatPlotLibNet.Mcp is a Model Context Protocol server. A model can render any of these chart types from a JSON spec and look at the result. When the spec is wrong, the server reports which field is wrong instead of returning a blank picture.

1.14 added the control room: Plt.OpsDashboard() and the tile anatomy arrived with it. The releases since then contain the fixes and extensions that real control-room use required: a secondary Y axis with the same capabilities as the primary axis, streaming that draws in SVG, 3-D axis titles that do not overlap their own labels, tile captions that wrap and stay inside their tile, and an ops window whose ticks are formatted as time.

After that, releases follow what the community needs: bug fixes, documentation, and whatever comes up in real use. Open a Discussion or an Issue; that is what decides the next release. Every release, with its migration notes, is listed in the CHANGELOG.

Quality bar: every class must pass a strict coverage gate of ≥90 % line and branch coverage (706 classes, at 99.6 % line / 97.5 % branch) across 11,757 tests. The test suite verifies rendering against matplotlib pixel-fidelity fixtures.

Documentation

• Wiki — getting started, cheatsheet, all 83 chart types, the control room, styling, streaming, SignalR, packages
• From matplotlib to C# — the pyplot call you know, and the line that draws it here
• Cookbook — copy-paste examples with rendered output
• Playground — try charts live in the browser
• API Reference — generated from the XML docs
• Benchmarks · Coverage policy · CHANGELOG

Packages

Quick start

using MatPlotLibNet;
using MatPlotLibNet.Styling;

double[] x = [1, 2, 3, 4, 5];
double[] y = [2, 4, 3, 5, 1];

Plt.Create()
    .WithTitle("My First Chart")
    .WithTheme(Theme.Dark)
    .AddSubPlot(1, 1, 1, ax => ax
        .Plot(x, y, s => { s.Color = Colors.Blue; s.Label = "Data"; })
        .WithLegend())
    .Save("chart.svg");

Features