kenlaikh/image-blob-reduce

Resize image blobs with high quality. Pica's wrapper to work with file inputs.

image-blob-reduce - downscale blobs with images inside

Wrapper for pica to work with blobs, with some sugar.

This is pica wrapper for convenient work with images from file input fields. While pica works with raw bitmaps, this package operates with "image files". Additional features are:

• [jpeg] Apply orientation to downscaled result.
• [jpeg] Keep metadata, but with patched orientation & removed original color profile.
• Easy to monkey-patch for your needs.

Demo

Install

npm install image-blob-reduce

Usage

const reduce = require('image-blob-reduce')();

//...

reduce
  .toBlob(image_blob, { maxWidth: 1000, maxHeight: 1000 })
  .then(blob => { ... });

API

new ImageBlobReduce([options])

Create new reducer. Options:

• pica - instance of pica, if you wish different defaults or shareable webworkers pool.

Short call: require('image_blob_reduce')()

.toBlob(in_blob, options) => Promise(out_blob)

Downscale image to fit into maxWidth*maxHeight size. If blob contains jpeg, then orientation is applied and metadata from original image reused (with minimal change).

Options:

• maxWidth - max allowed image width.
• maxHeight - max allowed image height.
• pica .resize() options - alpha, unsharpAmount, unsharpRadius, unsharpThreshold, cancelToken

.toCanvas(in_blob, options) => Promise(out_canvas)

The same as .toBlob(), but with canvas output.

.utils

require('./lib/utils'), to simplify modifications.

Reexports

More relinking:

• ImageBlobReduce.pica => require('pica')
• ImageBlobReduce.utils => require('./lib/utils')