how to increase png resolution with altair.renderers.enable("png")

[zyxue]

I'm using altair in a notebook, I tried

altair.renderers.enable("png", scale_factor=3.0)

it doesn't seem to have any effect on the resolution of the generated png. What's the right way to do so, please?

[ausiddiqui]

Facing the same. Installed using the conda method on macOS 11.2.3 running python 3.7 and altair 4.10 and vega-lite-cli 5.17.0. I also tried passing webdriver='firefox' and webdriver='chrome' and it made no impact. Additionally the axis tick labels are a much lighter style than the level visible on my browser (Safari using Jupyter Lab).

[pfei-sa]

Try altair_saver.save(plot, "plot.png", vega_cli_options=["-s 4"]) where 4 is the scaling factor

[JavierMedel]

specify the width and height using the properties I hope it helps.

altair_saver.save(bars.properties(width=800, height=400), "plot.png", vega_cli_options=["-s 4"])

[aecio]

This seems to work when using notebooks without having to use the save() function:

alt.renderers.enable('altair_saver', fmts=['png'], embed_options={'scaleFactor': '4'})

[joelostblom]

Since Altair 5.2, the functionality of Altair Saver is now available in Altair via the vl-convert package. Most of the functionality has been available since 5.0, and the main addition in 5.2 was PDF export. See the docs on how to save charts for more details. This includes how to set the resolution https://altair-viz.github.io/user_guide/saving_charts.html#png-figure-size-resolution

We are going to archive this repo, so I'm closing all the open issues and PRs before doing so. Try out the new options for saving charts mentioned above and if you run into issues, please open an issue directly in the altair or vl-convert repo.