Crate plotters

Plotters - Another Plotting Library in Rust

Plotters is a flexible drawing library for data visualization written in pure Rust. The library isn't aimed supporting different types of plotting, but a generic platform that can be extended to support different types of visualization methods.

Quick Start

use plotters::prelude::*;
fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut backend = BitMapBackend::new("examples/outputs/0.png", (640,480));
    backend.open()?;
    let root:DrawingArea<_,_> = backend.into();
    let font = Into::<FontDesc>::into("DejaVu Serif").resize(20.0);
    root.fill(&RGBColor(255,255,255))?;
    let mut chart = ChartBuilder::on(&root)
        .caption("y=x^2", &font)
        .build_ranged::<RangedCoordf32, RangedCoordf32, _, _>(-1f32..1f32, 0f32..1f32);

    chart.configure_mesh()
        .draw()?;
    
    chart.draw_series(LineSeries::new(
        (-50..=50).map(|x| x as f32 / 50.0).map(|x| (x, x*x)),
        &RGBColor(255, 0, 0),
    ))?;

    root.close()?;
    return Ok(());
}

Concepts by examples

Drawing Backends

Plotters can use different drawing backends, such as SVG, BitMap, etc. And even real-time rendering, such as library. For example a bitmap drawing backend.

use plotters::prelude::*;
fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create a 800*600 bitmap and start drawing
    let mut backend = BitMapBackend::new("examples/outputs/1.png", (300,200));
    // And if we want SVG backend
    // let backend = SVGBackend::new("output.svg", (800, 600));
    backend.open()?;
    backend.draw_rect((50,50), (200, 150), &RGBColor(255,0,0), true)?;
    backend.close()?;
    return Ok(());
}

And this will produce

Drawing Area

Plotters use a concept called drawing area for layout purpose. Plotters support multiple plot integrate in a single image. This is done by craeting sub drawing areas.

Besides that, drawing area also allows customized cooridnate system, by doing so, the coordinate mapping is done by the drawing area automatically.

use plotters::prelude::*;
fn main() -> Result<(), Box<dyn std::error::Error>> {
    let backend = BitMapBackend::new("examples/outputs/2.png", (300, 200));
    // A backend object can be converted into a drawing area
    let root_drawing_area:DrawingArea<_,_> = backend.into();
    // And we can split the drawing area into 3x3 grid
    let child_drawing_areas = root_drawing_area.split_evenly((3,3));
    // Then we fill the drawing area with different color
    for (area,color) in child_drawing_areas.into_iter().zip(0..) {
        area.fill(&Plattle99::pick(color))?;
    }
    root_drawing_area.close()?;
    return Ok(());
}

And this will produce

Elements

In Plotters, elements are build blocks of a image. All elements are able to draw on a drawing area. There are different types of elements, such as, lines, texts, circles, etc.

You may also combining existing elements to build a complex element.

use plotters::prelude::*;
fn main() -> Result<(), Box<dyn std::error::Error>> {
    let backend = BitMapBackend::new("examples/outputs/3.png", (300, 200));
    // A backend object can be converted into a drawing area
    let root:DrawingArea<_,_> = backend.into();
    // Draw an circle on the drawing area
    root.draw(&Circle::new((100,100), 50, Into::<ShapeStyle>::into(&RGBColor(255, 0, 0)).filled()))?;
    root.close()?;
    return Ok(());
}

And this will produce

Composable Elements

Besides the basic elements, elements can be composed into a logic group we called composed elements. When composing new elements, the upper-left conner is given in the target coordinate, and a new pixel based coordinate which has the upper-left conner defined as (0,0) is used for further element composition purpose.

For example, we can have an element which includes a dot and its coordinate.

use plotters::prelude::*;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let backend = BitMapBackend::new("examples/outputs/4.png", (640, 480));
    // A backend object can be converted into a drawing area
    let root:DrawingArea<_,_> = backend.into();
    root.fill(&RGBColor(255,255,255))?;

    let root = root.apply_coord_spec(RangedCoord::<RangedCoordf32, RangedCoordf32>::new(0f32..1f32, 0f32..1f32, (0..640, 0..480)));
    let font = Into::<FontDesc>::into("DejaVu Serif").resize(15.0);

    let dot_and_label = |x:f32,y:f32| {
        return EmptyElement::at((x,y))
               + Circle::new((0,0), 3, Into::<ShapeStyle>::into(&RGBColor(0,0,0)).filled())
               + OwnedText::new(format!("({:.2},{:.2})", x, y), (10, 0), &font);
    };

    root.draw(&dot_and_label(0.5, 0.6))?;
    root.draw(&dot_and_label(0.25, 0.33))?;
    root.draw(&dot_and_label(0.8, 0.8))?;
    root.close()?;
    return Ok(());
}

Plotting

Extending Plotters

Modules

chart
data
drawing
element
prelude
series
style