thumbsup-downsize

Convert / resize / transcode / down-sample photos & videos to be web-friendly

This is one of the core modules of thumbsup.github.io.

Setup

npm install thumbsup-downsize --save

This module requires GraphicsMagick and FFMpeg on the target system, available in the system path.

Usage

const downsize = require('thumbsup-downsize')

const options = { height: 100, width: 100 }
downsize.image('source.tiff', 'thumb.jpg', options, (err) => {
  console.log(err || 'Thumbnail created successfully')
})

API

.image

.image(source, target, options, callback)

Processes the image in source and creates a new image in target. The image is appropriately converted if needed based on the target file extension. Optionally specify options to resize the image:

// don't resize, just convert
opts = {}

// proportionally resize the photo to a maximum height
opts = {height}

// proportionally resize the photo to a maximum width
opts = {width}

// resize and crop the photo to exactly height x width (aspect ratio preserved)
opts = {height, width}

.still

.still(source, target, options, callback)

Extract a single frame from the video in source, and writes the image to target. Optionally specify options to resize the image:

// don't resize
opts = {}

// proportionally resize the still to a maximum height
opts = {height}

// proportionally resize the still to a maximum width
opts = {width}

// resize and crop the still to exactly height x width (aspect ratio preserved)
opts = {height, width}

.video

.video(source, target, options, callback)

Transcodes the video in source to a web-friendly format and lower bitrate, and writes it in target. Currently doesn't support any options, simply pass an empty hash ({}).

The .video() call returns an EventEmitter to follow the progress of the conversion, since it can take a long time.

const emitter = downsize.video(/* ... */)
emitter.on('progress', percent => console.log(`${percent}%`))

Contributing

Image/video resizing is hard to unit test. Instead, this repo contains an integration test suite made of many different resized files, covering different file formats and edge cases.

When submitting a change, make sure you run the build locally.

npm test

If you don't have all dependencies installed, you can also run the tests in Docker.

docker build -t downsize-test .
docker run downsize-test