how to save png when not running from jupyter

[asoliverez]

Hi, I can use weave().to_widget().auto_save_png() to save a chart when running from a jupyter notebook

However, I have an application that runs multiple reports from a CLI and I want to include this one. I tried the same .auto_save_png() command as in jupyter, and it doesn't save a png. It doesn't do anything, not even throw an error.

Is it because I should be using a different widget outside of jupyter?

[ricklupton]

Hi, the widget only works within the Jupyter notebook (the Sankey diagram is rendered to SVG/PNG in your browser).

To run outside Jupyter, if SVG is ok instead of PNG, probably the best way is to export to JSON using weave().to_json(filename, format="widget"), save to a file, then use svg-sankey.

$ svg-sankey test.json > test.svg

(see svg-sankey --help for options for margins, size etc)

This is working for me currently, but note that the JSON format is a work in progress (we're working on a JSON schema specification that will fix it) and is likely to change a bit.

If you need PNG you could then convert the SVG images using a tool like convert.

[QuLogic]

Relatedly, Matplotlib contains a way to make Sankey plots, though I cannot say whether one is easier or harder to use, and Matplotlib's likely has no real maintainer. But if no interactivity is required, then that may be an option.

[nickynicolson]

Broken link to svg-sankey above: should be https://github.com/ricklupton/svg-sankey

[ricklupton]

@nickynicolson Thanks, updated the link above.

[anirban6908]

I installed svg-sankey following the instructions here and exported .json file for the quickstart example. But running svg-sankey on the example I get this error

$ svg-sankey --size 800,600 --margins 10,150 test.json > test.svg
/usr/lib/node_modules/svg-sankey/index.es5.js:134
    return d.data.value;
                 ^

TypeError: Cannot read property 'value' of undefined
    at /usr/lib/node_modules/svg-sankey/index.es5.js:134:18
    at /usr/lib/node_modules/svg-sankey/node_modules/d3-sankey-diagram/build/d3-sankey-diagram.cjs.js:1200:14
    at Array.forEach (native)
    at buildGraph (/usr/lib/node_modules/svg-sankey/node_modules/d3-sankey-diagram/build/d3-sankey-diagram.cjs.js:1191:15)
    at sankey (/usr/lib/node_modules/svg-sankey/node_modules/d3-sankey-diagram/build/d3-sankey-diagram.cjs.js:1293:13)
    at drawDiagram (/usr/lib/node_modules/svg-sankey/index.es5.js:158:12)
    at /usr/lib/node_modules/svg-sankey/index.es5.js:37:15
    at tryToString (fs.js:457:3)
    at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:444:12)

Not sure how to resolve this. Thanks

[anki-code]

I've got the same error. The lib doesn't working in Jupyter Lab and hasn't ability to save image without Jupyter. It looks like ship in the bottle 😄

Could anyone recommend the alternative library?