Sharp: Is it possible to use vips_arrayjoin from sharp?

[NDevTK]

I would like to create an image from an array of image buffers with x number of images per row.

[lovell]

Hello, this isn't supported at the moment, but could make a future possible enhancement.

I recommend spawning a vips child process to do this right now - see https://github.com/lovell/sharp/issues/1175#issuecomment-377678250

The general use case for image stitching suggests this could be exposed via a utility function that would provide a "join" operation/pipeline only so e.g. no resizing at the same time.

👇 PROPOSED API, NOT YET IMPLEMENTED OR AVAILABLE

sharp
  .join([
    [image1, image2],
    [image3, image4]
  ], {
    background: '#fff',
    halign: 'centre',
    shim: 10
  })
  .toBuffer()
  .then( ... )

☝️ PROPOSED API, NOT YET IMPLEMENTED OR AVAILABLE

...where image1 are either filenames or Buffer objects (no Streams). Note also that a 2D array should probably be passed in (to be flattened internally to the 1D array expected by vips_arrayjoin.

[NDevTK]

Is there a way to use the bundled libvips from the child process? https://github.com/lovell/sharp/issues/1175#issuecomment-379417216

[NDevTK]

for .join() would it be possible to pass a 2d array that gets split up if there’s a across parameter. I think vips_arrayjoin() already has an across parameter

[lovell]

Is there a way to use the bundled libvips from the child process?

Only shared libraries are included, no executable files.

[NDevTK]

How do you use a child process

const { execFileSync  } = require('child_process');
function combine(images){
    const child = execFileSync('vips', ['arrayjoin', images, '--across 8', 'output.jpg']);
}

images is "img-0.jpg img-1.jpg img-2.jpg img-3.jpg img-4.jpg img-5.jpg img-6.jpg img-7.jpg img-8.jpg img-9.jpg img-10.jpg img-11.jpg img-12.jpg img-13.jpg img-14.jpg img-15.jpg img-16.jpg img-17.jpg img-18.jpg img-19.jpg img-20.jpg img-21.jpg img-22.jpg img-23.jpg img-24.jpg img-25.jpg img-26.jpg img-27.jpg img-28.jpg img-29.jpg img-30.jpg img-31.jpg img-32.jpg img-33.jpg img-34.jpg img-35.jpg img-36.jpg img-37.jpg img-38.jpg img-39.jpg img-40.jpg img-41.jpg img-42.jpg img-43.jpg img-44.jpg img-45.jpg img-46.jpg img-47.jpg"
But when I run it i get Unknown option --across 8 however if I run vips arrayjoin "img-0.jpg img-1.jpg img-2.jpg img-3.jpg img-4.jpg img-5.jpg img-6.jpg img-7.jpg img-8.jpg img-9.jpg img-10.jpg img-11.jpg img-12.jpg img-13.jpg img-14.jpg img-15.jpg img-16.jpg img-17.jpg img-18.jpg img-19.jpg img-20.jpg img-21.jpg img-22.jpg img-23.jpg img-24.jpg img-25.jpg img-26.jpg img-27.jpg img-28.jpg img-29.jpg img-30.jpg img-31.jpg img-32.jpg img-33.jpg img-34.jpg img-35.jpg img-36.jpg img-37.jpg img-38.jpg img-39.jpg img-40.jpg img-41.jpg img-42.jpg img-43.jpg img-44.jpg img-45.jpg img-46.jpg img-47.jpg" --across 8 output.jpg from the project directory in cmd it works and creates the output.jpg file

[lovell]

I think you need to specify --across and 8 as separate arguments. This is a Node thing unrelated to sharp or libvips.

[willemmulder]

@lovell Is this still planned? Would be very useful!

[lovell]

@willemmulder PRs are always welcome, if you're able.

[willemmulder]

@lovell Not just yet, unfortunately. I'm just getting started, and looking for a way to stitch together a bunch of smaller images. I previously implemented things in jimp but now started to look into Sharp because jimp was so memory-hungry (using >2GB for stitching 196 small images).

[willemmulder]

@lovell Is there a way in Sharp to make raw calls to libvips? So I could call the arrayjoin function through Sharp?