Charming - A Rust Visualization Library

Charming is a powerful and versatile chart rendering library for Rust that leverages the power of Apache ECharts to deliver high-quality data visualizations. Built with the Rust programming language, this library aims to provide the Rust ecosystem with an intuitive and effective way to generate and visualize charts, using a declarative and user-friendly API.

Highlights:

Easy-to-use, declaritive API.
Abundant chart types with rich and customizable chart themes and styles.
Ready to use in WebAssembly environments.
Rendering to multiple formats, including HTML, SVG, PNG, JPEG, GIF, WEBP, PNM, TIFF, TGA, DDS, BMP, ICO, HDR, OPENEXR, FARBFELD, AVIF, and QOI.

Themes

Default	Dark	Vintage
Westeros	Essos	Wonderland
Walden	Chalk	Infographic
Macarons	Roma	Shine
Purple Passion	Halloween

Future versions of Charming will support custom themes.

Basic Usage

Add charming as a dependency:

$ cargo add charming

Refer to the documentation of the Chart struct for how to create a chart with various components.

Once you create a chart, you can render it into various format. Charming provides three types of renderers:

HTML renderer: HtmlRenderer renders a chart into an HTML fragments and offloads the actual rendering to user's web browser for an interactive, seamless experience. This renderer is useful when you want to render a chart on the client side, e.g., in a web application.
Image renderer: ImageRenderer renders a chart into an image file. This renderer makes use of an embed deno_core engine to execute the JavaScript code of Echarts and generate an image file. This renderer is disabled by default, and you need to enable the ssr (Server-Side Rendering) feature to use it.
WASM renderer: WasmRenderer renders a chart in a WebAssembly runtime. This renderer is disabled by default, and you need to enable the wasm feature to use it. Note that the wasm feature and ssr feature are mutually exclusive.

Here is an example of drawing a simple pie chart into an SVG file:

use charming::{
    component::Legend,
    element::ItemStyle,
    series::{Pie, PieRoseType},
    Chart, ImageRenderer
};

fn main() {
    let chart = Chart::new()
        .legend(Legend::new().top("bottom"))
        .series(
            Pie::new()
                .name("Nightingale Chart")
                .rose_type(PieRoseType::Radius)
                .radius(vec!["50", "250"])
                .center(vec!["50%", "50%"])
                .item_style(ItemStyle::new().border_radius(8))
                .data(vec![
                    (40.0, "rose 1"),
                    (38.0, "rose 2"),
                    (32.0, "rose 3"),
                    (30.0, "rose 4"),
                    (28.0, "rose 5"),
                    (26.0, "rose 6"),
                    (22.0, "rose 7"),
                    (18.0, "rose 8"),
                ]),
        );

    let mut renderer = ImageRenderer::new(1000, 800);
    renderer.save(&chart, "/tmp/nightingale.svg");
}

This code creates the following SVG file:

As another example, the code file gallery/src/dataset/encode_and_matrix.rs draws a complex chart with four sub-charts:

Crate Feature Flags

The following two feature flags are available, note that they can't be used together:

ssr - Enables the ImageRenderer, which provides the capability to generate image files.
wasm - Enables the WasmRenderer, which provides the capability to render charts in WebAssembly runtime.

Renderers

// Use HtmlRenderer.
use charming::HtmlRenderer;

// Chart dimension 1000x800.
let renderer = HtmlRenderer::new("my charts", 1000, 800);
// Render the chart as HTML string.
let html_str = renderer.render(&chart).unwrap();
// Save the chart as HTML file.
renderer.save(&chart, "/tmp/chart.html").unwrap();

// Use ImageRenderer. The `ssr` feature needs to be enabled.
use charming::{ImageRenderer, ImageFormat};

// Chart dimension 1000x800.
let mut renderer = ImageRenderer::new(1000, 800);
// Render the chart as SVG string.
renderer.render(&chart).unwrap();
// Render the chart as PNG bytes.
renderer.render_format(ImageFormat::Png, &chart).unwrap();
// Save the chart as SVG file.
renderer.save(&chart, "/tmp/chart.svg").unwrap();
// Save the chart as PNG file.
renderer.save_format(ImageFormat::Png, &chart, "/tmp/chart.png");

// Use WasmRenderer. The `wasm` feature needs to be enabled.
use charming::WasmRenderer;

// Chart dimension 1000x800.
let renderer = WasmRenderer::new(1000, 800);
// Render the chart in the WebAssembly runtime
renderer.render(&chart).unwrap();

Themes

Charming supports a number of themes out of the box. You can use the Theme enum to specify a theme for your chart. For instance, the following code snippet shows how to use the Westeros theme:

use charming::{Chart, ImageRenderer};
use charming::theme::Theme;
use charming::component::Title;

ImageRenderer::new(1000, 800).theme(Theme::Westeros).save(
    &Chart::new().title(Title::new().text("Westeros")),
    "/tmp/westeros.svg",
);

Future versions of Charming will support custom themes.