imagemagick-cli

node-imagemagick-cli

Access the ImageMagick CLI tools from Node. Cross-platform, with support for ImageMagick 6 and 7.

• Introduction
• Compatibility
• API
• Debugging
• Prior Art / Design Goals
• Coding
  • Creating a Release
• License

Introduction

This library is designed to provide a safe and platform independent way of calling the ImageMagick CLI tools.

It is safe because it correctly deals with the Windows convert issue. It is platform independent because you don't have to worry about how it deals with the issue.

Install with npm:

npm install --save imagemagick-cli

To call an ImageMagick CLI tool, just run:

const imagemagickCli = require('imagemagick-cli');
imagemagickCli.exec('convert -version');

This command will work consistently on MacOSX, Windows and Linux. On Windows, it will not conflict with the system installed convert.exe tool.

Compatibility

This libary is tested with the following platforms and ImageMagick versions:

Platform	ImageMagick Version
OSX	6 ✅
OSX	7 ✅
Ubuntu	6 ✅
Ubuntu	7 ✅
Windows	6 ✅
Windows	7 ✅

API

Execute a command:

imagemagickCli
    .exec('convert -version')
    .then(({ stdout, stderr }) => {
        console.log(`Output: ${stdout}`);
    });

Check the ImageMagick version:

imagemagickCli
    .getVersion()
    .then((version) => {
        console.log(`Version: ${version}`);
    });

If the version cannot be identified (most likely because ImageMagick is not installed) then the function resolves with null.

Debugging

This library uses the node-debug module. To see low-level debugging information when using this library, set imagemagick-cli as part of the DEBUG environment variable:

DEBUG=imagemagick-cli node ./my-script.js

With debugging enabled, the full command sent to the CLI, as well as all stderr and stdout output is shown in the log.

Prior Art / Design Goals

I made this library to deal with some issues relating to Windows in the app-icon project, which I didn't have to deal with again in other projects (like app-splash.

There are some great and sophisticated modules around for working with IM:

• https://github.com/rsms/node-imagemagick
• https://github.com/yourdeveloper/node-imagemagick (which is the active fork of the above)
• https://github.com/elad/node-imagemagick-native

I decided to create my own library because I don't need apis for ImageMagick in my use cases, just a platform agnostic way to call the CLI tools. The design goals for this project are that it allows you to run IM CLI tools without having to worry about platform or version nuances, that's it.

If you need more functionality I recommend looking into the projects above.

Coding

The only dependencies are Node 6 (or above).

Useful commands for development are:

Command	Usage
npm test	Runs the unit tests.
npm run test:debug	Runs the tests in a debugger. Combine with .only and debugger for ease of debugging.
npm run cov	Runs the tests, writing coverage reports to ./artifacts/coverage.
npm run lint	Lint the code, using airbnb.

Creating a Release

To create a release.

• Merge your work to master.
• Use npm run release to bump and update the changelog
• Push and deploy git push --follow-tags && npm publish

License

MIT