poloto 4.0.3

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

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

    let range = (0..200).map(|x| (x as f64 / 200.0) * 10.0 - 5.0);

    let g1 = gaussian(1.0, 0.0);
    let g2 = gaussian(0.5, 0.0);
    let g3 = gaussian(0.3, 0.0);

    let mut plotter = poloto::plot("gaussian", "x", "y", f64::default_ctx(), f64::default_ctx());

    plotter.line("σ = 1.0", range.clone().map(|x| [x, g1(x)]));
    plotter.line("σ = 0.5", range.clone().map(|x| [x, g2(x)]));
    plotter.line("σ = 0.3", range.clone().map(|x| [x, g3(x)]));

    println!("{}", poloto::disp(|a| plotter.simple_theme(a)));
}

Output

Data Example

use poloto::num::timestamp::{UnixTime, UnixTimeContext};
use poloto::prelude::*;
// PIPE me to a file!
fn main() {
    //fake hourly trend over one day.
    let trend: [i128; 24] = [
        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 day1 = (2020, 1, 30);

    let timezone = &chrono::Local;

    let data = trend
        .into_iter()
        .zip(0..)
        .map(|(x, i)| (UnixTime::from_ymd_hms(timezone, day1, i, 0, 0), x));

    let mut s = poloto::plot(
        "Number of rides at theme park hourly",
        "Hour",
        "Number of rides",
        UnixTimeContext::new(timezone).with_tick_fmt(|w, v, _, _| {
            use chrono::Timelike;
            write!(w, "{}", v.datetime(timezone).hour())
        }),
        i128::default_ctx().with_marker(0),
    );
    s.histogram("", data);

    println!("{}", poloto::disp(|a| s.simple_theme(a)));
}

Output

Collatz Example

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

    let mut plotter = poloto::plot("collatz", "x", "y", i128::default_ctx(), i128::default_ctx().with_marker(0));
    for i in 1000..1006 {
        plotter.line(poloto::formatm!("c({})", i), (0..).zip(collatz(i)));
    }

    println!(
        "{}<style>{}{}</style>{}{}",
        poloto::simple_theme::SVG_HEADER,
        poloto::simple_theme::STYLE_CONFIG_DARK_DEFAULT,
        ".poloto_line{stroke-dasharray:2;stroke-width:1;}",
        poloto::disp(|a| plotter.render(a)),
        poloto::simple_theme::SVG_END
    )
}

Output

Parametric Example

// PIPE me to a file!
use poloto::prelude::*;
fn main() {
    // https://mathworld.wolfram.com/HeartCurve.html
    let heart = |t: f64| {
        [
            16.0 * t.sin().powi(3),
            13.0 * t.cos() - 5.0 * (2.0 * t).cos() - 2.0 * (3.0 * t).cos() - (4.0 * t).cos(),
        ]
    };

    let range = (0..100).map(|x| x as f64 / 100.0).map(|x| x * 6.0 - 3.0);

    let mut plotter = poloto::plot(
        "Heart Graph",
        "x",
        "y",
        f64::default_ctx().with_marker(-20.0).with_marker(20.0),
        f64::default_ctx().with_marker(-20.0).with_marker(20.0),
    );

    plotter.line_fill_raw("heart", range.map(heart));
    plotter.preserve_aspect();

    println!("{}", poloto::disp(|a| plotter.simple_theme_dark(a)));
}

Output

Trig Example

use poloto::prelude::*;
// PIPE me to a file!
fn main() {
    let x = (0..500).map(|x| (x as f64 / 500.0) * 10.0);

    let mut plotter = poloto::plot(
        "Some Trigonometry Plots 🥳",
        formatm!("This is the {} label", 'x'),
        "This is the y label",
        f64::default_ctx(),
        f64::default_ctx(),
    );

    // Using poloto::Croppable, we can filter out plots and still have discontinuity.
    plotter.line(
        "tan(x)",
        x.clone()
            .map(|x| [x, x.tan()])
            .crop_above(10.0)
            .crop_below(-10.0)
            .crop_left(2.0),
    );

    plotter.line("sin(2x)", x.clone().map(|x| [x, (2.0 * x).sin()]));

    plotter.line(
        "2*cos(x)",
        x.clone().map(|x| [x, 2.0 * x.cos()]).crop_above(1.4),
    );

    println!("{}", poloto::disp(|a| plotter.simple_theme(a)));
}

Output

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 tagger dependency crate.

CSS Usage Example

See the graphs in this report: broccoli_book

CSS classes

Below are the css classes that can be stylized. There are default styles settings for these css classes in the static strings STYLE_CONFIG_LIGHT_DEFAULT and STYLE_CONFIG_DARK_DEFAULT.

These are the css classes added through Plotter::render

  • poloto_text - all poloto text
  • poloto_axis_lines - axis lines and ticks
  • poloto_tick_labels - x and y labels as well as where labels
  • poloto_labels - title, x label, ylabel
  • poloto_title - title
  • poloto_xname - xlabel
  • poloto_yname - ylabel
  • poloto_legend_text - legend text
  • poloto_legend_icon - legend icon
  • poloto_scatter - scatter plots and legend icon
  • poloto_line - line plots and legend icon
  • poloto_histo - histogram and legend icon
  • poloto_linefill - line fill and legend icon
  • poloto_linefillraw - line fill raw and legend icon

These are the css classes added through poloto::SVG_HEADER which is used by simple_theme and simple_theme_dark.

  • poloto - default svg element

For plots:

  • 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)

Iterating plots twice

In order to calculate the right size view to scale all the plots, poloto has to iterate over all the plot points twice. Once to find the min and max bounds, and once to scale all the points by the scale determined by the first iteration.

If you are using an iterator where each iteration is expensive, consider running the iterator just once, collecting the results in a Vec. Then pass that Vec to the plotting functions. Beware of passing the buffer directly to the plotter! If you do this, you'll use a lot of memory since the plotter will clone the whole buffer. Instead pass a reference to the buffer. See the second example below.

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 embeded 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.