chartjs_image

Crates.iochartjs_image
lib.rschartjs_image
version6.1.13
created_at2025-12-29 15:09:48.353663+00
updated_at2026-01-19 11:43:42.430504+00
descriptionRender Chart.JS as Image (or URL of Image)
homepagehttps://www.image-charts.com/
repositoryhttps://github.com/image-charts/chartjs-image-rust
max_upload_size
id2010724
size177,551
Francois-Guillaume Ribreau (FGRibreau)

documentation

https://docs.rs/chartjs_image

README

Chart.js image rust library logo

Crates.io Documentation License

Libraries.io dependency status for GitHub repo

Generate Chart.JS charts as image and embed them everywhere in emails, pdf reports, chat bots...!

Getting started

1. Add Chart.js Image to your project

Crates.io

Requirements: Rust 1.65+

Add to your Cargo.toml:

[dependencies]
chartjs_image = "6"

Feature Flags

  • async (default): Enables async methods (to_buffer(), to_file(), to_data_uri())
  • blocking: Enables blocking/sync methods (to_buffer_blocking(), to_file_blocking(), to_data_uri_blocking())
  • full: Enables both async and blocking
# Async only (default)
chartjs_image = "6"

# Blocking only
chartjs_image = { version = "6", default-features = false, features = ["blocking"] }

# Both async and blocking
chartjs_image = { version = "6", features = ["full"] }

2. Import ChartJSImage library

use chartjs_image::ChartJSImage;

3. Generate a chart image

use chartjs_image::ChartJSImage;

fn main() {
    let chart = ChartJSImage::new()
        .chart(r#"{
            "type": "pie",
            "data": {
                "labels": ["Red", "Blue", "Yellow"],
                "datasets": [{
                    "data": [300, 50, 100]
                }]
            }
        }"#)
        .width("600")
        .height("300");

    // Get URL (sync, no HTTP request)
    let url = chart.to_url();
    println!("{}", url);
}

// Async example
use chartjs_image::ChartJSImage;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let chart = ChartJSImage::new()
        .chart(r#"{"type":"pie","data":{"labels":["Red","Blue"],"datasets":[{"data":[60,40]}]}}"#)
        .width("600")
        .height("300");

    // Download as bytes
    let buffer = chart.to_buffer().await?;

    // Save to file
    chart.to_file("chart.png").await?;

    // Get as data URI
    let data_uri = chart.to_data_uri().await?;
    // data:image/png;base64,iVBORw0KGgo...

    Ok(())
}

Table of Contents

Constructor

Create an instance with builder pattern. See usage

// Free usage - default configuration
let chart = ChartJSImage::new();

// Enterprise & Enterprise+ subscriptions
let chart = ChartJSImage::builder()
    .secret("SECRET_KEY")
    .build();

// With custom timeout
let chart = ChartJSImage::builder()
    .secret("SECRET_KEY")
    .timeout(std::time::Duration::from_secs(10))
    .build();

// On-premise subscriptions
let chart = ChartJSImage::builder()
    .protocol("https")
    .host("custom-domain.tld")
    .port(443)
    .pathname("/chart.js/2.8.0")
    .secret("SECRET_KEY")
    .build();

Methods

to_url() -> String

Get the full Image-Charts API url (signed and encoded if necessary)

Usage
use chartjs_image::ChartJSImage;

fn main() {
    let url = ChartJSImage::new()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("700")
        .height("300")
        .to_url();

    println!("{}", url);
}

to_buffer() -> Result<Vec<u8>, ChartJSImageError> (async)

to_buffer_blocking() -> Result<Vec<u8>, ChartJSImageError> (blocking)

Do a request to Image-Charts API with current configuration and yield image bytes

Usage (async)
use chartjs_image::ChartJSImage;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let buffer = ChartJSImage::new()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("700")
        .height("300")
        .to_buffer()
        .await?;

    println!("Downloaded {} bytes", buffer.len());
    Ok(())
}
Usage (blocking)
use chartjs_image::ChartJSImage;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let buffer = ChartJSImage::new()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("700")
        .height("300")
        .to_buffer_blocking()?;

    println!("Downloaded {} bytes", buffer.len());
    Ok(())
}

to_file(path) -> Result<(), ChartJSImageError> (async)

to_file_blocking(path) -> Result<(), ChartJSImageError> (blocking)

Download chart and save to file

Usage (async)
use chartjs_image::ChartJSImage;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    ChartJSImage::new()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("700")
        .height("300")
        .to_file("chart.png")
        .await?;

    println!("Chart saved!");
    Ok(())
}

to_data_uri() -> Result<String, ChartJSImageError> (async)

to_data_uri_blocking() -> Result<String, ChartJSImageError> (blocking)

Do a request to Image-Charts API with current configuration and yield a base64 encoded data URI

Usage (async)
use chartjs_image::ChartJSImage;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let data_uri = ChartJSImage::new()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("100")
        .height("100")
        .to_data_uri()
        .await?;

    // Use in HTML: <img src="{data_uri}" />
    println!("{}", &data_uri[..50]);
    Ok(())
}

Enterprise Support

Image-Charts Enterprise and Enterprise+ subscriptions remove the watermark and enable advanced features like custom-domain, high-resolution charts, custom fonts, multiple axis and mixed charts.

Usage

Once subscribed to a plan you will receive an ACCOUNT_ID and a SECRET_KEY. These two parameters are mandatory to sign your request and remove the watermark. Replace both values in the code example below:

use chartjs_image::ChartJSImage;

fn main() {
    let url = ChartJSImage::builder()
        .secret("SECRET_KEY")
        .build()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("700")
        .height("190")
        .icretina("1")
        .icac("ACCOUNT_ID")
        .to_url();

    println!("{}", url);
}

On-Premise Support

Image-Charts virtual appliance can be deployed anywhere inside a customer network.

use chartjs_image::ChartJSImage;

fn main() {
    let url = ChartJSImage::builder()
        .host("custom-domain.tld")
        .secret("SECRET_KEY")
        .build()
        .chart(r#"{"type":"pie","data":{"labels":["Hello","World"],"datasets":[{"data":[60,40]}]}}"#)
        .width("700")
        .height("190")
        .icretina("1")
        .icac("ACCOUNT_ID")
        .to_url();

    println!("{}", url);
    // https://custom-domain.tld/chart.js/2.8.0?c=...&ichm=...
}

c( value ) -> ChartJSImage

Javascript/JSON definition of the chart. Use a Chart.js configuration object.

Usage
.c("{type:'bar',data:{labels:['Q1','Q2','Q3','Q4'],datasets:[{label:'Users',data:[50,60,70,180]},{label:'Revenue',data:[100,200,300,400]}]}}")

chart( value ) -> ChartJSImage

Javascript/JSON definition of the chart. Use a Chart.js configuration object.

Usage
.chart("{type:'bar',data:{labels:['Q1','Q2','Q3','Q4'],datasets:[{label:'Users',data:[50,60,70,180]},{label:'Revenue',data:[100,200,300,400]}]}}")

width( value ) -> ChartJSImage

Width of the chart

Usage
.width("400")

height( value ) -> ChartJSImage

Height of the chart

Usage
.height("300")

backgroundColor( value ) -> ChartJSImage

Background of the chart canvas. Accepts rgb (rgb(255,255,120)), colors (red), and url-encoded hex values (%23ff00ff). Abbreviated as "bkg"

Usage
.backgroundColor("black")
 
.backgroundColor("rgb(255,255,120)")
 
.backgroundColor("%23ff00ff")

bkg( value ) -> ChartJSImage

Background of the chart canvas. Accepts rgb (rgb(255,255,120)), colors (red), and url-encoded hex values (%23ff00ff). Abbreviated as "bkg"

Usage
.bkg("black")
 
.bkg("rgb(255,255,120)")
 
.bkg("%23ff00ff")

encoding( value ) -> ChartJSImage

Encoding of your "chart" parameter. Accepted values are url and base64.

Allowed values:
.encoding("url")
 
.encoding("base64")

icac( value ) -> ChartJSImage

image-charts enterprise account_id

Reference

Usage
.icac("accountId")

ichm( value ) -> ChartJSImage

HMAC-SHA256 signature required to activate paid features

Reference

Usage
.ichm("0785cf22a0381c2e0239e27c126de4181f501d117c2c81745611e9db928b0376")

icretina( value ) -> ChartJSImage

retina mode

Reference

Allowed values:
.icretina("0")
 
.icretina("1")
Commit count: 18

cargo fmt