HTML to Image in Node.js

This page describes how to convert web pages and HTML to images in Node.js using the Pdfcrowd API. The API is easy to use and the integration takes only a few of lines of code.

Samples

Installation

Install the client library from npm
npm install pdfcrowd

We also offer other installation options.

Authentication

Authentication is needed in order to use the Pdfcrowd API. The credentials used for accessing the API are your Pdfcrowd username and the API key.

You can try out the API without registration using the following demo credentials:
  • Username: demo
  • API key: ce544b6ea52a5621fb9d55f8b542d14d

To get your personal API credentials, you can start a free API trial or buy the API license.

Getting Started

Enter a web page or upload an HTML file to get an image preview and integration code that you can copy and paste to your application.

Or you can choose from the examples below and adapt the code to your needs. You can also interactively explore the API in the API Playground.

Examples

var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertUrlToFile(
    "http://www.example.com",
    "example.png",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// use predefined callback for saving to a file
var callbacks = pdfcrowd.saveToFile("example.png");

// set custom error callback
callbacks.error = function(errMessage, statusCode) {
    if(statusCode) {
        console.error("Pdfcrowd Error: " + statusCode + " - " + errMessage);
    } else {
        console.error("Pdfcrowd Error: " + errMessage);
    }
};

// run the conversion and write the result to a file
client.convertUrl("http://www.example.com", callbacks);
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertFileToFile(
    "/path/to/MyLayout.html",
    "MyLayout.png",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// use predefined callback for saving to a file
var callbacks = pdfcrowd.saveToFile("MyLayout.png");

// set custom error callback
callbacks.error = function(errMessage, statusCode) {
    if(statusCode) {
        console.error("Pdfcrowd Error: " + statusCode + " - " + errMessage);
    } else {
        console.error("Pdfcrowd Error: " + errMessage);
    }
};

// run the conversion and write the result to a file
client.convertFile("/path/to/MyLayout.html", callbacks);
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertStringToFile(
    "<html><body><h1>Hello World!</h1></body></html>",
    "HelloWorld.png",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// use predefined callback for saving to a file
var callbacks = pdfcrowd.saveToFile("HelloWorld.png");

// set custom error callback
callbacks.error = function(errMessage, statusCode) {
    if(statusCode) {
        console.error("Pdfcrowd Error: " + statusCode + " - " + errMessage);
    } else {
        console.error("Pdfcrowd Error: " + errMessage);
    }
};

// run the conversion and write the result to a file
client.convertString("<html><body><h1>Hello World!</h1></body></html>", callbacks);
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

// configure the conversion
try {
    client.setOutputFormat("png");
    client.setDebugLog(true);
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertFileToFile(
    "/path/to/MyLayout.html",
    "MyLayout.png",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
        
        // print URL to the debug log
        console.log("Debug log url: " + client.getDebugLogUrl());
        
        // print the number of available conversion credits in your account
        console.log("Remaining credit count: " + client.getRemainingCreditCount());
        
        // print the number of credits consumed by the conversion
        console.log("Consumed credit count: " + client.getConsumedCreditCount());
        
        // print the unique ID of the conversion
        console.log("Job id: " + client.getJobId());
        
        // print the size of the output in bytes
        console.log("Output size: " + client.getOutputSize());
    });

Integration Examples

The API can be easily integrated into your environment. You can have our interactive API Playground autogenerate the integration code for you:

Common Customizations

The API lets you convert a web page, a local HTML file, or a string containing HTML. The result of the conversion can be stored to a local file, to a stream object or to a variable. See the conversion input section for more details.

The best way to start with the API is to choose one of the examples and once you get it working, you can further customize the code. You can find the most common customizations in the table below.

Image size Set image dimensions with setScreenshotWidth and setScreenshotHeight.
Image format Specify a different output image format with setOutputFormat.
Hide or remove elements You can use the following classes in your HTML code to hide or remove elements from the output:
  • pdfcrowd-remove - sets display:none!important on the element
  • pdfcrowd-hide - sets visibility:hidden!important on the element
Learn about other options.
Use @media print You can switch to the print version of the page (if it exists) with setUsePrintMedia.
Run custom JavaScript You can use setOnLoadJavascript or setCustomJavascript to alter the HTML contents with a custom JavaScript. In addition to the standard browser APIs, the custom JavaScript code can use helper functions from our JavaScript library .
Custom CSS styling You can alter CSS styling used during conversion with a custom JavaScript or using the pdfcrowd-body CSS class, which is automatically set on the HTML <body> element. You can, for example, set the H1 height to 48px by adding the following line to your CSS:
.pdfcrowd-body h1 { font-size: 48px; }

Template Rendering

The API enables rendering of HTML templates. The template syntax is based on the Jinja template rendering engine.

The most common constructs are:

  • Data rendering: Invoice: {{ invoice.number }}
  • For loop: {% for invoice in invoices %} ... {% endfor %}
  • If statement: {% if invoice.total > 100 %} ... {% endif %}
  • Data filter: {{ invoice.to.first_name|capitalize }}

The supported input data formats are JSON, XML, CSV and YAML. The data can be uploaded from a file or from a string variable.

Supported template filters: capitalize, center, default, escape, first, forceescape, format, indent, join, last, length, list, lower, replace, reverse, safe, slice, sort, string, striptags, title, trim, truncate, unique, upper, wordcount, wordwrap.

Template Rendering Examples

var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToPdfClient("{{ user_name }}", "{{ api_key }}");

// configure the conversion
try {
    client.setDataString(`{
            "name": "World",
            "product": "Pdfcrowd API"
        }`);
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertStringToFile(
    "Hello {{ name }} from {{ product }}",
    "output.pdf",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToPdfClient("{{ user_name }}", "{{ api_key }}");

// configure the conversion
try {
    client.setDataString(`<?xml version="1.0" encoding="UTF-8"?>
        <data>
          <name>World</name>
          <product>Pdfcrowd API</product>
        </data>`);
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertStringToFile(
    "Hello {{ data.name }} from {{ data.product }}",
    "output.pdf",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToPdfClient("{{ user_name }}", "{{ api_key }}");

// configure the conversion
try {
    client.setDataString(`name: World
product: Pdfcrowd API`);
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertStringToFile(
    "Hello {{ name }} from {{ product }}",
    "output.pdf",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });
var pdfcrowd = require("pdfcrowd");

// create the API client instance
var client = new pdfcrowd.HtmlToPdfClient("{{ user_name }}", "{{ api_key }}");

// configure the conversion
try {
    client.setDataString(`name,product
World,Pdfcrowd API`);
} catch(why) {
    // report the error
    console.error("Pdfcrowd Error: " + why);
    process.exit(1);
}

// run the conversion and write the result to a file
client.convertStringToFile(
    "Hello {{ name }} from {{ product }}",
    "output.pdf",
    function(err, fileName) {
        if (err) return console.error("Pdfcrowd Error: " + err);
        console.log("Success: the file was created " + fileName);
    });

Error Handling

try {
    // call the API 
}
catch(why) {
    // print error
    console.error("Pdfcrowd Error: " + why);

    // print just error code
    console.error("Pdfcrowd Error Code: " + why.getCode());

    // print just error message
    console.error("Pdfcrowd Error Message: " + why.getMessage());

    // or handle the error in your way
}

Troubleshooting

API Method Reference

Refer for details to the API Method Reference.