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javascriptimagenode.jsimage-processingimage-manipulation

Which library should I use for server-side image manipulation on Node.JS?

I found a quite large list of available libraries on Node.JS wiki but I'm not sure which of those are more mature and provide better performance. Basically I want to do the following:

  1. load some images to a server from external sources
  2. put them onto one big canvas
  3. crop and mask them a bit
  4. apply a filter or two
  5. Resize the final image and give a link to it

Big plus if the node package works on both Linux and Windows.

Solution

  • Answering my own question

    I spent two days digging through Node.js graphics libraries.

    node-canvas

    • I tried it first since I'm quite familiar with <canvas> API. It's a huge plus for a library.
    • it requires Cairo which doesn't have an easy Windows download. I found it in GTK+ distribution though.
    • moreover it needs native library binding code to be compiled on module installation. It uses Node-Waf which hasn't being ported to Windows yet.

    gm

    • mature
    • runs on Windows smoothly
    • docs are ok but not thorough: I had to look up into source code to figure out what API is available
    • unfortunately there's no easy way to combine images with gm. Maybe there's some way to achieve that but I haven't found one after two hours spent with it.

    node-imagemagick

    • The official repo has very few basic ImageMagick commands covered but I used this fork (good thing that NPM can pull libraries directly from git repositories). It has bindings for montage which does exactly what I need.
    • ImageMagick is quite slow, though it works on Windows.

    Node-Vips

    • Huge plus: it uses an incredible VIPS library which I'm familiar with. VIPS is very fast and optimized for large images. It's very smart about utilizing hardware resources: if your machine has a lot of RAM it'll do all processing in memory but will switch to hard-drive caches if memory is scarce or required for other applications.
    • same as node-canvas it requires Node-Waf so it's not available for Windows yet.

    sharp

    • also VIPS-based. Actively maintained as of 2024. Sample usage to convert an input buffer to 320x240 and PNG format, and get an output buffer out:

      const sharp = require('sharp');
const outBuf = await sharp(inBuf).resize(320, 240, { fit: 'fill' })
  .png().toBuffer()

    I also looked at other libraries from the list but most of them are either very immature or do not suit my use case. I would really like to try migrating to either Node-Canvas or Node-Vips when Node-Waf gets ported to Windows but until then I'll stick to node-imagemagick.