sorccunode-jpeg-turbo
node-jpeg-turbo provides minimal libjpeg-turbo bindings for Node.js. It is very, very fast compared to other alternatives, such as node-imagemagick-native or jpeg-js.
Please ask if you need more methods exposed.
Requirements
We use NAN to guarantee maximum v8 API compatibility, so in theory any Node.js or io.js version should work fine. For maximum convenience we also use node-pre-gyp to publish prebuilt binaries for a few common platforms. For example, if you're on OS X and using the latest stable Node, you probably won't need to do a thing.
If you must build from source
First, if you're building from the repo, make sure to init and update submodules or you'll get confusing errors about missing targets when building. We include libjpeg-turbo as a submodule.
git submodule init
git submodule update(or just use git clone --recursive when cloning the repo)
Due to massive linking pain on Ubuntu, we embed and build libjpeg-turbo directly with node-gyp. Unfortunately this adds an extra requirement, as the build process needs yasm to enable all optimizations. Note that this step is only required for x86 and x86_64 architectures. You don't need yasm if you're building on arm, for example.
Here's how to install yasm:
On OS X
brew install yasmOn Ubuntu 14.04
apt-get install yasmOn Ubuntu 12.04
apt-get install yasmImportant! Ubuntu 12.04 comes with GCC 4.6, which is too old to compile the add-on (and most other modules since Node.js 4.0 was released). More information is available here.
If you really must use this module on Ubuntu 12.04, the following may work:
apt-get install python-software-properties
add-apt-repository -y ppa:ubuntu-toolchain-r/test
apt-get -y install g++-4.8
export CXX=g++-4.8Remember to export CXX when you npm install.
On Debian
apt-get install yasmOn Alpine Linux
apk add yasmOthers
Search your package manager for yasm.
Installation
Make sure you've got the requirements installed. Then simply install from NPM:
npm install --save jpeg-turboAPI
jpg.bufferSize(options) → Number
If you'd like to preallocate a Buffer for jpg.compressSync(), use this method to get the worst-case upper bound. The options argument is fully compatible with the jpg.compressSync() method, so that you can pass the same options to both functions.
- options is an Object with the following properties:
- width Required. The width of the image.
- height Required. The height of the image.
- subsampling Optional. The subsampling method to use. Defaults to
jpg.SAMP_420.
- Returns The
Numberof bytes required in a worst-case scenario.
var fs = require('fs')
var jpg = require('jpeg-turbo')
var raw = fs.readFileSync('raw.rgba')
var options = {
format: jpg.FORMAT_RGBA,
width: 1080,
height: 1920,
subsampling: jpg.SAMP_444,
}
var preallocated = new Buffer(jpg.bufferSize(options))
var encoded = jpg.compressSync(raw, preallocated, options)jpg.compressSync(raw[, out], options) → Buffer
Compresses (i.e. encodes) the raw pixel data into a JPG. This method is not capable of resizing the image.
For efficiency reasons you may choose to encode into a preallocated Buffer. While fast, it has a number of drawbacks. Namely, you'll have to be careful not to reuse the buffer in async processing before processing (e.g. saving, displaying or transmitting) the entire encoded image. Otherwise you risk corrupting the image. Also, it wastes a huge amount of space compared to on-demand allocation.
- raw is a
Bufferwith the raw pixel data inoptions.format. - out is an optional preallocated
Bufferfor the encoded image. The size of the buffer is checked. Seejpg.bufferSize()for an example of how to preallocate a sufficientBuffer. If not given, memory is allocated and reallocated as needed, which eliminates most of the wasted space but is slower and lacks consistency with varying source images. - options is an Object with the following properties:
- format Required. The format of the
rawpixel data (e.g.jpg.FORMAT_RGBA). - width Required. The width of the image.
- height Required. The height of the image.
- subsampling Optional. The subsampling method to use. Defaults to
jpg.SAMP_420. - quality Optional. The desired JPG quality. Defaults to 80.
- format Required. The format of the
- Returns The encoded image as a
Buffer. Note that the buffer may actually be a slice of the preallocatedBuffer, if given. Be careful not to reuse the preallocated buffer before you've finished processing the encoded image, as it may corrupt the image.
var fs = require('fs')
var jpg = require('jpeg-turbo')
var raw = fs.readFileSync('raw.rgba')
var options = {
format: jpg.FORMAT_RGBA,
width: 1080,
height: 1920,
subsampling: jpg.SAMP_444,
}
var encoded = jpg.compressSync(raw, options)See jpg.bufferSize() for an example of preallocated Buffer usage.
jpg.decompressSync(image[, out], options) → Object
Decompresses (i.e. decodes) the JPG image into raw pixel data.
- image is a
Bufferwith the JPG image data. - out is an optional preallocated
Bufferfor the decoded image. The size of the buffer is checked, and should be at leastwidth * height * bytes_per_pixelor larger. If not given, one is created for you. The only benefit of providing theBufferyourself is that you can reuse the same buffer between multiplejpg.decompressSync()calls. Note that this can lead to issues with concurrency. Seejpg.compressSync()for related discussion. - options is an Object with the following properties:
- format Required. The desired format of the
rawpixel data (e.g.jpg.FORMAT_RGBA). - out Deprecated. Use the
outargument instead.
- format Required. The desired format of the
- Returns An
Objectwith the following properties:- data A
Bufferwith the raw pixel data. - width The width of the image.
- height The height of the image.
- subsampling The subsampling method used in the JPG.
- size Deprecated. Use
data.lengthinstead. - bpp The number of bytes per pixel.
- data A
var fs = require('fs')
var jpg = require('jpeg-turbo')
var image = fs.readFileSync('image.jpg')
var options = {
format: jpg.FORMAT_RGBA,
}
var decoded = jpg.decompressSync(image, options)Thanks
- https://github.com/A2K/node-jpeg-turbo-scaler
- https://github.com/mash/node-imagemagick-native
- https://github.com/google/skia/blob/master/gyp/libjpeg-turbo.gyp
- https://github.com/openstf/android-libjpeg-turbo
License
See LICENSE.
Copyright © Simo Kinnunen. All Rights Reserved.