[−][src]Crate plotters
Plotters - Another Plotting Library in Rust
Plotters is a flexible drawing library for data visualization written in pure Rust for both native and WebAssembly.
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Why plotting in Rust? Although rendering a figure doesn't requires too many computation power in most of the case, and programming language such as Python and Javascript is used for visualization purpose. Sometimes we need to make a figure based on huge amount of data, for example, rendering some human gene data may requires to downsampling trillions data points, which isn't even doable with many high-level programming language. In this case, Rust is a perfect candidate for rendering figures, since it runs very fast while having high-level abstraction abilities.
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What type of figure is supported? Currently, we support line series, point series and candlestick series. And the library is designed to be able to render multiple figure into a single image. But Plotter is aimed to be a platform that is fully extendable to supporting any other types of figure.
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Plotting on HTML5 canvas Plotters currently supports backend that uses the HTML5 canvas. To use the WASM support, you can simply create
CanvasBackend
instead of other backend and all other API remains the same! Check the demo that uses Plotters with WASM at here. An sample WASM application is avaiable at examples/wasm-demo. To try it just simply run the shell scriptstart-server.sh
under that directory. And the demo is avaiable at this link as well.
Gallery
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("Arial").resize(50.0); root.fill(&White)?; let mut chart = ChartBuilder::on(&root) .caption("y=x^2", &font) .x_label_area_size(30) .y_label_area_size(30) .build_ranged(-1f32..1f32, -0.1f32..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), &Red, 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(&Palette99::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(); root.fill(&White); // Draw an circle on the drawing area root.draw(&Circle::new((100,100), 50, Into::<ShapeStyle>::into(&Green).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(240,200,200))?; let root = root.apply_coord_spec(RangedCoord::<RangedCoordf32, RangedCoordf32>::new(0f32..1f32, 0f32..1f32, (0..640, 0..480))); let font = Into::<FontDesc>::into("Arial").resize(15.0); let dot_and_label = |x:f32,y:f32| { return EmptyElement::at((x,y)) + Circle::new((0,0), 3, ShapeStyle::from(&Black).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(()); }
Chart Context
In order to draw a chart, Plotters need an data object build on top of drawing area called ChartContext
.
The chart context defines even higher level constructs compare to the drawing area.
For example, you can define the label areas, meshs, and put a data series onto the drawing area with the help
of the chart context object.
use plotters::prelude::*; fn main() -> Result<(), Box<dyn std::error::Error>> { let backend = BitMapBackend::new("examples/outputs/5.png", (640, 480)); let root:DrawingArea<_,_> = backend.into(); root.fill(&White); let root = root.margin(10,10,10,10); // After this point, we should be able to draw construct a chart context let font:FontDesc = Into::<FontDesc>::into("Arial").resize(40.0); // Create the chart object let mut chart = ChartBuilder::on(&root) // Set the caption of the chart .caption("This is our first plot", &font) // Set the size of the label region .x_label_area_size(20) .y_label_area_size(40) // Finally attach a coordinate on the drawing area and make a chart context .build_ranged(0f32..10f32, 0f32..10f32); // Then we can draw a mesh chart.configure_mesh() // We can customize the maxium number of labels allowed for each axis .x_labels(30) .y_labels(10) // We can also change the format of the label text .y_label_formatter(&|x| format!("{:.3}", x)) .draw()?; // And we can draw something in the drawing area let smaller_font = font.resize(10.0); chart.draw_series(LineSeries::new(vec![(0.0,0.0), (5.0, 5.0), (8.0, 7.0)], &Red))?; // Similarly, we can draw point series chart.draw_series(PointSeries::of_element(vec![(0.0,0.0), (5.0, 5.0), (8.0, 7.0)], 5, &Red, &|c,s,st| { return EmptyElement::at(c) // We want to construct a composed element on-the-fly + Circle::new((0,0),s,st.filled()) // At this point, the new pixel coordinate is established + OwnedText::new(format!("{:?}", c), (10, 0), &smaller_font); }))?; root.close()?; return Ok(()); }
Modules
chart | The high-level chartting utils. |
coord | The abstraction of the coordinate system |
data | The data processing module, which implmements algorithm related to visualization of data. Such as, downsampling, etc. |
drawing | The drawing utils for Plotter. Which handles the both low-level and high-level drawing. |
element | Defines the drawing elements, the high-level drawing unit in Plotters drawing system |
prelude | The module imports the most commonly used types and modules in Plotters |
series | This module contains predefined types of series.
The series in Plotters is actually an iterator of elements, which
can be taken by |
style | The style for shapes and text, font, color, etc. |