sharp
adj
- clearly defined; distinct: a sharp photographic image.
- quick, brisk, or spirited.
- shrewd or astute: a sharp bargainer.
- (Informal.) very stylish: a sharp dresser; a sharp jacket.
The typical use case for this high speed Node.js module is to convert a large JPEG image to smaller JPEG images of varying dimensions.
It is somewhat opinionated in that it only deals with JPEG images, always obeys the requested dimensions by either cropping or embedding and insists on a mild sharpen of the resulting image.
Under the hood you'll find the blazingly fast libvips image processing library, originally created in 1989 at Birkbeck College and currently maintained by the University of Southampton.
Performance is 4x-8x faster than the imagemagick equivalent, based mainly on the number of CPU cores available.
Prerequisites
Requires Node.js v0.8+, node-gyp and libvips-dev to build.
sudo npm install -g node-gyp
sudo apt-get install libvips-dev
Requires vips-7.xx.pc (installed with libvips-dev) to be symlinked as /usr/lib/pkgconfig/vips.pc
Ubuntu 12.04 LTS:
sudo ln -s /usr/lib/pkgconfig/vips-7.26.pc /usr/lib/pkgconfig/vips.pc
Ubuntu 13.04 (64-bit):
sudo ln -s /usr/lib/x86_64-linux-gnu/pkgconfig/vips-7.28.pc /usr/lib/pkgconfig/vips.pc
Install
npm install sharp
Usage
var sharp = require("sharp");
crop(inputPath, outputPath, width, height, callback)
Scale and crop JPEG inputPath
to width
x height
and write JPEG to outputPath
calling callback
when complete.
Example:
sharp.crop("input.jpg", "output.jpg", 300, 200, function(err) {
if (err) {
throw err;
}
});
embedWhite(inputPath, outputPath, width, height, callback)
Scale and embed JPEG inputPath
to width
x height
using a white canvas and write JPEG to outputPath
calling callback
when complete.
sharp.embedWhite("input.jpg", "output.jpg", 200, 300, function(err) {
if (err) {
throw err;
}
});
embedBlack(inputPath, outputPath, width, height, callback)
Scale and embed JPEG inputPath
to width
x height
using a black canvas and write JPEG to outputPath
calling callback
when complete.
sharp.embedBlack("input.jpg", "output.jpg", 200, 300, function(err) {
if (err) {
throw err;
}
});
Testing
npm install --dev sharp
npm test
Performance
AMD Athlon 4x core 3.3GHz 512KB L2
- imagemagick x 5.55 ops/sec ±0.68% (31 runs sampled)
- sharp x 24.49 ops/sec ±6.85% (64 runs sampled)
AWS t1.micro
- imagemagick x 1.36 ops/sec ±0.96% (11 runs sampled)
- sharp x 12.42 ops/sec ±5.84% (64 runs sampled)
AWS m1.medium
- imagemagick x 1.38 ops/sec ±0.45% (11 runs sampled)
- sharp x 12.66 ops/sec ±5.54% (65 runs sampled)
AWS c1.medium
- imagemagick x 2.10 ops/sec ±0.67% (15 runs sampled)
- sharp x 18.97 ops/sec ±10.54% (52 runs sampled)
AWS m3.xlarge
- imagemagick x 4.46 ops/sec ±0.33% (26 runs sampled)
- sharp x 28.89 ops/sec ±7.75% (74 runs sampled)