Experimental node.js binding for libvips built on ffi

Status

It's mostly complete, it seems stable, and it passes the tests suite with no errors or leaks. It can reliably thumbnail 10,000 jpeg images in constant memory and without falling over. Probably.

Example

var vips = require('vips');

var image = vips.Image.newFromFile(process.argv[2]);
image = image.crop(100, 100, image.width - 200, image.height - 200);

image = image.reduce(1.0 / 0.9, 1.0 / 0.9, {kernel: 'linear'});

var mask = vips.Image.newFromArray(
  [[-1,  -1, -1], 
   [-1,  16, -1], 
   [-1,  -1, -1]], 8);
image = image.conv(mask, {precision: 'integer'});

image.writeToFile(process.argv[3]);

`async`

node-vips is synchronous by default, but you can call any operation with the special async option, for example:

image.writeToFile('file.jpg', {
  Q: 90,
  async: (err, result) => {
    if (err) {
      throw err;
    }
  }
});

image.max({
  async: (err, result) => {
    if (err) {
      throw err;
    }

    console.log('maximum value in image is ' + result);
  }
});

Most operations are instant -- it only makes sense to use async for things which will trigger a pixel loop.

References

https://github.com/node-ffi/node-ffi

https://github.com/TooTallNate/ref

https://github.com/TooTallNate/ref-array

https://github.com/TooTallNate/ref-struct

https://github.com/TooTallNate/weak

https://github.com/node-ffi/node-ffi/wiki/Node-FFI-Tutorial

Actions

Install everything

npm install

Run the tests

npm test

Run a single test with the GC enabled

./node_modules/.bin/mocha --expose-gc test/unit/image.js

Regenerate convenience wrappers

vips = require('vips');
vips.generateWrappers();

and copy output to lib/autogen.js.