Added typst renderer to support png/pdf/jpg/svg exports

[wirhabenzeit]

This is a pull request addressing https://github.com/juba/pyobsplot/issues/23

Supported output formats are

• pdf
• png
• svg (including title, caption etc)

Example

from pyobsplot import Obsplot, Plot
import polars as pl

penguins = pl.read_csv("https://github.com/juba/pyobsplot/raw/main/doc/data/penguins.csv")
op = Obsplot(renderer="typst", dpi=300, font="SF Pro Display", font_size=14, margin=4)

op({
    "color": {"legend": True},
    "marginLeft": 80,
    "marginRight": 80,
    "title": "Penguin body mass by island",
    "x": {"inset": 20},
    "grid": True,
    "marks": [
        Plot.boxX(penguins, {
            "x": "body_mass_g", "fill": "island", "y": "island", "fy": "species"
        })
    ]
})

results in

Writing to file

op(spec, path="file.png")

saves the output to a file

Issues

• One minor issue is that some font needs to be installed on the system supporting glyphs like → (RIGHTWARDS ARROW', U+2192). I am using SF Pro Display which is free.
• I am not sure how to handle options. For my taste a global option like

op = Obsplot(renderer="typst", dpi=300, font="SF Pro Display", font_size=14, margin=4)

over something like

op(spec, path="file.png", dpi=300, font="SF Pro Display", font_size=14, margin=4)