#svg #css #plot #chart #plotting

poloto

Simple 2D plotting library that outputs SVG and can be styled using CSS

159 stable releases (17 major)

17.1.0 Dec 4, 2022
17.0.13 Nov 30, 2022
16.2.6 Oct 17, 2022
15.2.0 Jun 21, 2022
0.12.1 Mar 7, 2021

#4 in Visualization

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482 downloads per month
Used in 4 crates

MIT license

160KB
4K SLoC

You can find poloto on github and crates.io. Documentation at docs.rs

A simple 2D plotting library that outputs graphs to SVG that can be styled using CSS.

Poloto graphs can be stylized using css either directly in the SVG, or from inside of html with an embedded svg. The latter allows the user to dynamically match the svg to their website's theme. The user can take full advantage of CSS, adding highlight on hover, animation, shadows, strokes, etc. Check out the github examples to see this. The latest graph outputs of the examples can be found in the assets folder.

You can see it in action in this rust book broccoli-book

Gaussian Example

use poloto::build;
// PIPE me to a file!
fn main() {
    // See https://en.wikipedia.org/wiki/Gaussian_function
    let gau = |sigma: f64, mu: f64| {
        use std::f64::consts::TAU;
        let s = sigma.powi(2);
        let k = (sigma * TAU).sqrt().recip();
        move |x: f64| [x, (-0.5 * (x - mu).powi(2) / s).exp() * k]
    };

    let xs = poloto::util::range_iter([-5.0, 5.0], 200);

    let plots = poloto::plots!(
        build::plot("σ=1.0").line(xs.clone().map(gau(1.0, 0.0))),
        build::plot("σ=0.5").line(xs.clone().map(gau(0.5, 0.0))),
        build::plot("σ=0.3").line(xs.clone().map(gau(0.3, 0.0)))
    );

    poloto::data(poloto::plots!(build::origin(), plots))
        .build_and_label(("gaussian", "x", "y"))
        .append_to(poloto::header().light_theme())
        .render_stdout();
}

Output

demo

Collatz Example

use hypermelon::prelude::*;
use poloto::build;

// PIPE me to a file!
fn main() {
    let collatz = |mut a: i128| {
        std::iter::from_fn(move || {
            if a == 1 {
                None
            } else {
                a = if a % 2 == 0 { a / 2 } else { 3 * a + 1 };
                Some(a)
            }
        })
        .fuse()
    };

    let svg = poloto::header().with_viewbox_width(1200.0);

    let opt = poloto::render::render_opt()
        .with_tick_lines([true, true])
        .with_viewbox(svg.get_viewbox())
        .move_into();

    let style =
        poloto::render::Theme::dark().append(".poloto_line{stroke-dasharray:2;stroke-width:2;}");

    let a = (1000..1006).map(|i| build::plot(format!("c({})", i)).line((0..).zip(collatz(i))));

    poloto::data(poloto::plots!(poloto::build::origin(), a))
        .map_opt(|_| opt)
        .build_and_label(("collatz", "x", "y"))
        .append_to(svg.append(style))
        .render_stdout();
}

Output

demo

Timestamp Example

use poloto::build;
use poloto::num::timestamp::UnixTime;
fn main() {
    let timezone = &chrono::Utc;
    use chrono::TimeZone;

    //Source https://en.wikipedia.org/wiki/Men%27s_long_jump_world_record_progression
    let data = [
        (7.61, "05 August 1901"),
        (7.69, "23 July 1921"),
        (7.76, "07 July 1924"),
        (7.89, "13 June 1925"),
        (7.90, "07 July 1928"),
        (7.93, "09 September 1928"),
        (7.98, "27 October 1931"),
        (8.13, "25 May 1935"),
        (8.21, "12 August 1960"),
        (8.24, "27 May 1961"),
        (8.28, "16 July 1961"),
        (8.31, "10 June 1962"),
        (8.33, "25 May 1963"),
        (8.34, "12 September 1964"),
        (8.35, "29 May 1965"),
        (8.35, "19 October 1967"),
        (8.90, "18 October 1968"),
        (8.95, "30 August 1991"),
    ];

    let data = data.map(|(x, y)| {
        let d = timezone.from_utc_date(&chrono::NaiveDate::parse_from_str(y, "%d %B %Y").unwrap());
        (UnixTime::from(d), x)
    });

    let plots = poloto::plots!(
        build::plot("").line(data),
        build::markers([], [0.0])
    );

    poloto::data(plots)
        .build_and_label((
            "Long Jump world record progression",
            "Date",
            "Mark (in meters)",
        ))
        .append_to(poloto::header().light_theme())
        .render_stdout();
}

Output

demo

Custom Ticks Example

use hypermelon::format_move;
use poloto::build;
fn main() {
    // hourly trend over one day.
    let trend = vec![
        0, 0, 0, 0, 0, 3, 5, 5, 10, 20, 50, 60, 70, 50, 40, 34, 34, 20, 10, 20, 10, 4, 2, 0,
    ];

    let plots = poloto::plots!(
        build::plot("").histogram((0..).zip(trend)),
        build::markers([24], [])
    );

    let data = poloto::data(plots);

    let ticks =
        poloto::ticks::from_iter((0..).step_by(6)).with_tick_fmt(|&v| format_move!("{} hr", v));

    data.map_xticks(|_| ticks)
        .build_and_label(("title", "x", "y"))
        .append_to(poloto::header().light_theme())
        .render_stdout();
}

Output

demo

Bar example

fn main() {
    let data = [
        (20, "potato"),
        (14, "broccoli"),
        (53, "pizza"),
        (30, "avocado"),
    ];

    poloto::build::bar::gen_simple("", data, [0])
        .label(("Comparison of Food Tastiness", "Tastiness", "Foods"))
        .append_to(poloto::header().light_theme())
        .render_stdout();
}

Output

demo

Styling example

use hypermelon::prelude::*;
use poloto::{build, prelude::OutputZip};
fn main() {
    let theme = poloto::render::Theme::light();

    // Style the first plot and its legend image if it is a histogram.
    let theme =
        theme.append(".poloto0.poloto_histo.poloto_imgs{fill:red;stroke:black;stroke-width:2px}");

    // Some attributes have to accessed directly , so use >* to select the rects directly.
    let theme = theme.append(".poloto0.poloto_histo.poloto_imgs>*{rx:20px;ry:20px}");

    // Style the text of the first legend
    let theme = theme.append(".poloto0.poloto_legend.poloto_text{fill:blue;}");

    // Style all line plots but not legend img.
    let theme = theme.append(".poloto_line.poloto_imgs.poloto_plot{stroke:purple;stroke-width:20px;stroke-dasharray:40px}");

    // Style all line plot legend imgs.
    let theme = theme.append(".poloto_line.poloto_imgs.poloto_legend{stroke:purple;stroke-width:10px;stroke-dasharray:10px}");

    // Style the scatter plots but not legend img
    let theme = theme.append(".poloto_scatter.poloto_plot{fill:purple;stroke-width:20px;}");

    // Style the scatter plots but not legend img
    let theme = theme.append(".poloto_scatter.poloto_plot{fill:purple;stroke-width:20px;}");

    // Style the xaxis name
    let theme = theme.append(
        ".poloto_name.poloto_x{fill:orange;stroke-width:20px;font-size:30px;font-style: italic;}",
    );

    // Style the background
    let theme = theme.append(".poloto_background{fill:darkslategray;}");

    // Style the text
    let theme = theme.append(".poloto_text{fill: peru;}");

    // Style the ticks
    let theme = theme.append(".poloto_imgs.poloto_ticks{stroke:springgreen;}");

    let x = (0..50).map(|x| (x as f64 / 50.0) * 10.0);

    let data = poloto::plots!(
        build::plot("sin-10").histogram(x.clone().step_by(3).zip_output(|x| x.sin() - 10.)),
        build::plot("cos").line(x.clone().zip_output(|x| x.cos())),
        build::plot("sin-5").scatter(x.clone().step_by(3).zip_output(|x| x.sin() - 5.))
    );

    poloto::data(data)
        .build_and_label((
            "Demo: you can change the style of the svg file itself!",
            "x axis",
            "y axis",
        ))
        .append_to(poloto::header().append(theme))
        .render_stdout();
}

Output

demo

Usecases

Poloto converts each plot into svg elements like circles. Because of this its not really suitable for plots with many many plots. For those you might want to use a library to lets you plot directly to a png/jpg image instead. You can certainly rasterize the generated svg image, but generating and displaying the svg wont be all that efficient if there are a ton of plots.

cloned vs buffered plot iterators

poloto runs through plot iterators twice. Once to get the min/max bounds, and a second time to scale all the plots by those min/max bounds. There are two ways to do this. One is to just clone the iterator, and consume both. The second way is to accumulate the items from one iterator into a Vec<>, and then just iterate over that vec. By default, poloto will use a Vec backed buffer. However, you can configure it to clone the iterator instead.

//Uses vec backed buffer
let data=[[1.0,2.0],[2.0,3.0]];
poloto::build::plot("").line(data);


//Cloned the iterator
let it=(0..).take(10).zip(5..);
poloto::build::plot("").line(poloto::build::cloned(it));

Using the cloned method has pros and cons. The user has more control and can reduce memory usage. However they might accidentally increase memory usage.

Escape protection

If a user tried to inject html through the title/xname/yname/tick format/ or plot names, the html escapes will get turned into their encoded values. This protection is provided by the hypermelon dependency crate.

CSS Usage Example

See the graphs in this report: broccoli_book

CSS classes

  • poloto[n]fill - If the n'th plot requires fill. (e.g. linefill or histogram)
  • poloto[n]stroke - If the n'th plot requires stroke. (e.g. line or scatter)

Can I change the styling of the plots?

Yes! You can harness the power of CSS both in the svg, or outside in html with an embedded svg. Some things you can do:

  • Change the color scheme to fit your html theme.
  • Highlight one plot, make it dashed, or add hover effect
  • Animate things using @keyframes

The Plotter struct documents which css classes you can modify for the graph as a whole. Each plot function documents which css classes you can modify to change that specific plot.

Scatter plots are done using SVG paths made up of lines of zero length. This allows you to change the radius of the scatter dots by changing the stroke width.

Formatting Tick Intervals

Poloto will first print intervals in normal decimal at the precision required to capture the differences in the step size between the intervals. If the magnitude of a number is detected to be too big or small, it may switch to scientific notation, still at the required precision. It will only switch if the scientific notation version is actually less characters than the normal decimal format which is not always the case when you consider the precision that might be required to capture the step size.

Even with the above system, there are cases where the numbers all have a really big magnitude, but are all really close together (small step size). In this case, there isn't really a good way to format it. In these cases, poloto will fall back to making the number relative to the first number.

How to render to png?

You can use resvg. Install that, and then run a command similar to:

resvg -w 1200 target/assets/collatz.svg target/assets/collatz.png

Output

demo

Dependencies

~43–270KB