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node-html-to-image: Generate Images from HTML

 4 years ago
source link: https://github.com/frinyvonnick/node-html-to-image
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Welcome to node-html-to-image :sunrise_over_mountains:

A Node.js library that generates images from HTML

:house:Homepage

Description

This module exposes a function that generates images (png, jpeg) from HTML. It uses puppeteer in headless mode to achieve it. Additionally, it embarks Handlebars to provide a way to add logic in your HTML.

Install

npm install node-html-to-image
# or
yarn add node-html-to-image

Usage

const nodeHtmlToImage = require('node-html-to-image')

nodeHtmlToImage({
  output: './image.png',
  html: '<html><body>Hello world!</body></html>'
})
  .then(() => console.log('The image was created successfully!'))

Options

List of all available options:

option description type required ouput The ouput path for generated image string required html The html used to generate image content string required type The type of the generated image jpeg or png (default: png) optional content If provided html property is considered an handlebars template and use content value to fill it object optional waitUntil Define when to consider markup succeded. Learn more . string or Array optional puppeteerArgs The puppeteerArgs property let you pass down custom configuration to puppeteer. Learn more . object optional transparent The transparent property let you generate images with transparent background (for png type). boolean optional

Setting output image resolution

node-html-to-image takes a screenshot of the body tag's content. If you want to set output image's resolution you need to set its dimension using CSS like in the following example.

const nodeHtmlToImage = require('node-html-to-image')

nodeHtmlToImage({
  output: './image.png',
  html: `<html>
    <head>
      <style>
        body {
          width: 2480px;
          height: 3508px;
        }
      <style>
      </style>
    </head>
    <body>Hello world!</body>
  </html>
  `
})
  .then(() => console.log('The image was created successfully!'))

Example with Handlebars

Handlerbars is a templating language. It generates HTML from a template and an input object. In the following example we provide a template to node-html-to-image and a content object to fill the template.

const nodeHtmlToImage = require('node-html-to-image')

nodeHtmlToImage({
  output: './image.png',
  html: '<html><body>Hello {{name}}!</body></html>',
  content: { name: 'you' }
})
  .then(() => console.log('The image was created successfully!'))

Handlebars provides a lot of expressions to handle common use cases like conditions or loops.

Dealing with images

If you want to display an image which is stored remotely do it as usual. In case your image is stored locally I recommend having your image in base64 . Then you need to pass it to the template with the content property. Here is an example:

const nodeHtmlToImage = require('node-html-to-image')
const fs = require('fs');

const image = fs.readFileSync('./image.jpg');
const base64Image = new Buffer(bitmap).toString('base64');

nodeHtmlToImage({
  output: './image.png',
  html: '<html><body><img src="{{imageSource}}" /></body></html>',
  content: { imageSource: base64Image }
})

Related

Run tests

You need to install tesseract on your computer before launching tests. Here is the procedure for Mac users:

brew install tesseract
brew install tesseract-lang

Launch test:

yarn test

Author

:bust_in_silhouette: FRIN Yvonnick [email protected]

Contributing

Contributions, issues and feature requests are welcome!

Feel free to check issues page .

Show your support

Give a :star:️ if this project helped you!

:memo: License

Copyright © 2019 FRIN Yvonnick [email protected] .

This project is Apache--2.0 licensed.

This README was generated with :heart: by readme-md-generator


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