planex2d Python playground

planex2d is a Python library for exact 2D geometry: outlines from lines, arcs, circles and splines, Boolean operations, offsets and fillets, sketches with geometric constraints and driving dimensions, measurements, and the DXF, SVG and planar STEP files that carry them. The playground lets you try all of it without installing anything. It answers questions a drawing program leaves open, such as the moments of inertia of an odd profile, the thinnest wall of a part or the area that two outlines share, and it shows the result as a drawing you can zoom and hover. A link carries the code, so a question about a shape can be shared together with the code that answers it.

What a run shows

Every run starts from scratch, as a script: a fresh namespace, fresh automatic ids, and the code from the first line to the last. What it prints, its warnings and its errors appear on the right in the order they come, an error with the line it stopped at, which the editor marks. px.Plot draws with plotly, so the ids of the edges show on hover; matplotlib figures appear when the code calls plt.show(). When the last line is a value, it is shown too: a planex2d object is drawn, anything else printed.

What the code can import

The Python standard library, planex2d, numpy, plotly, ezdxf and svgelements load with the page. matplotlib, scipy and shapely load the first time the code imports them. Every package is pinned to one version, so the same code gives the same result tomorrow; any other import is reported before the code runs.

Sharing

Share puts the code, compressed, into the link after the # sign, together with the planex2d version it was written for. A link of a few dozen lines is a few hundred characters long; a link over 2,000 characters gets a warning, since some chat apps cut links that long. A shared link loads its code into the editor without running it, so you can read it first.

1. Load

   The page loads Python and planex2d into this tab. Your browser keeps both in its cache, so later visits start faster.

2. Write

   The editor is Monaco, the editor of VS Code. It keeps your code in this browser between visits.

3. Run

   Run or Ctrl+Enter sends the code to Python in this tab, which runs it and shows its output on the right.

4. Share

   Share copies a link that carries the code. Nothing is stored anywhere else.

Run it on your machine

The same code runs in Python on your machine. Install planex2d and see the documentation for everything it can do. Outside the playground, px.Plot draws with matplotlib unless it is given backend="plotly".

$ pip install planex2d

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Limits

• The playground has planex2d's core. The OpenCASCADE bindings, planex2d-occ, do not run in the browser yet, so nothing in 3D.
• A run cannot be interrupted. Stop starts Python again, which takes a few seconds once its packages are cached.
• In the browser, planex2d runs in one thread, so a long computation takes longer than in Python on your machine.
• Something does not work? Open an issue on GitHub with a share link if you can.