rsz

Resize images as files or Buffers

npm install rsz
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rsz Build Status

Resize image files or Buffers

Depends on node-canvas which has special build instructions as it requires Cairo to be installed on your system.

rsz shares the same API as crp, except crp is for cropping images rather than resizing. See also: sz for simply obtaining the size of an image, and thmb for making thumbnails of images.

API

There is one method but multiple ways to use it:

rsz(src, width, height, function (err, buf) { / / })

Where src is a String specifying the path to the image or a Buffer containing the image data, and buf is a Buffer containing the resized image data.

rsz(src, dst, width, height, function (err) { / / })

Where src is a String specifying the path to the image or a Buffer containing the image data, and dst is a String specifying the path to write the output file to.

rsz(src, { width: w, height: h }, function (err, buf) { / / })

Where w and h are the width and height respectively, src is a String specifying the path to the image or a Buffer containing the image data, and buf is a Buffer containing the resized image data.

rsz(src, dst, { width: w, height: h }, function (err) { / / })

Where w and h are the width and height respectively, src is a String specifying the path to the image or a Buffer containing the image data, and dst is a String specifying the path to write the output file to.

Options

By default, rsz will return a PNG Buffer or write a PNG file. You can change this when you pass an options object: { height: 100, width: 100, type: 'jpeg' }. You can also adjust the quality with a 'quality' property.

  • 'height' (Number, required) the height of the resized image
  • 'width' (Number, required) the width of the resized image
  • 'type' (String, optional, default: 'png') set to 'jpeg' to return a JPEG Buffer or write a JPEG file.
  • 'quality' (Number, optional) used when creating a JPEG, a number between 1 (lowest quality) and 100 (highest quality).
  • 'aspectRatio' (Boolean, optional, default: false) set to true to ensure resized image has the same aspect ratio as the original image.

Examples

var rsz = require('rsz')
  , fs  = require('fs')

// output resized image as a buffer

rsz('/path/to/nyancat.gif', 200, 350, function (err, buf) {
  fs.writeFileSync('/path/to/nyancat_200_350.png', buf)
})

// supply destination file directly

rsz('/path/to/nyancat.gif', 200, 350, '/path/to/nyancat_200_350.png', function (err) {
})

// configure the width and height with an options object

rsz('/path/to/nyancat.gif', { width: 200, height: 350 }, function (err, buf) {
  fs.writeFileSync('/path/to/nyancat_200_350.png', buf)
})

// combine options object and output destination

rsz('/path/to/nyancat.gif', { width: 200, height: 350 }, '/path/to/nyancat_200_350.png', function (err) {
})

// maintain aspect ratio

rsz('/path/to/nyancat.gif', { width: 200, height: 200, aspectRatio: true }, function (err, buf) {
})

// resize only one dimension

rsz('/path/to/nyancat.gif', { width: 200 }, function (err, buf) {

})

// resize only one dimension by setting the other dimension to 0

rsz('/path/to/nyancat.gif', 200, 0, function (err, buf) {

})

// rsz also supports convertion between gif, png & jpeg

rsz(
    '/path/to/avatar.png'
  , { width: 50, height: 50, type: 'jpeg', quality: 40 }
  , '/path/to/avatar_50_50.jpg'
  , function (err) {
      /* ... */
    }
)

Licence

rsz is Copyright (c) 2013 Rod Vagg @rvagg and licensed under the MIT licence. All rights not explicitly granted in the MIT license are reserved. See the included LICENSE file for more details.

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