gulp-scale-images
v3.0.3
Published
Gulp plugin to resize each image into multiple smaller variants.
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gulp-scale-images
Gulp plugin to make each image smaller. Combined with flat-map
, you can create multiple variantes per image, which is useful for responsive images.
Installing
npm install gulp-scale-images --save-dev
Usage
gulp-scale-images
expects the instructions for each file to be in file.scale
. They may look like this:
{
maxWidth: 300, // optional maximum width
maxHeight: 400, // optional maximum height
format: 'jpeg', // optional, one of ('jpeg', 'png', 'webp')
withoutEnlargement: false, // optional, default is true
fit: 'inside', // optional, default is 'cover', one of ('cover', 'contain', 'fill', 'inside', 'outside')
rotate: true, // optional
metadata: false, // copy metadata over?
formatOptions: {} // optional, additional format options for sharp engine
}
Note: You must specify at least one of maxWidth
and maxHeight
.
You can pass additional format options to Sharp engine using formatOptions
parameter. Docs can be found at Sharp API.
An example, we're going to generate two smaller variants for each input file. We're going to use flat-map
for this:
const gulp = require('gulp')
const flatMap = require('flat-map').default
const scaleImages = require('gulp-scale-images')
const twoVariantsPerFile = (file, cb) => {
const pngFile = file.clone()
pngFile.scale = {maxWidth: 500, maxHeight: 500, format: 'png'}
const jpegFile = file.clone()
jpegFile.scale = {maxWidth: 700, format: 'jpeg'}
cb(null, [pngFile, jpegFile])
}
gulp.src('src/*.{jpeg,jpg,png,gif}')
.pipe(flatMap(twoVariantsPerFile))
.pipe(scaleImages())
.pipe(gulp.dest(…))
Note: Unlike sharp
, gulp-scale-image
is not designed to process untrusted user input. For example, it turns off sharp
's input pixel limit altogether.
Definining scale instructions based on metadata
You can let gulp-scale-images
read the image metadata first, to device what to do with the file:
const readMetadata = require('gulp-scale-images/read-metadata')
const through = require('through2')
const scaleImages = require('gulp-scale-images')
const computeScaleInstructions = (file, _, cb) => {
readMetadata(file, (err, meta) => {
if (err) return cb(err)
file = file.clone()
file.scale = {
maxWidth: Math.floor(meta.width / 2),
maxHeight: Math.floor(meta.height / 2)
}
cb(null, file)
})
}
gulp.src(…)
.pipe(through.obj(computeScaleInstructions))
.pipe(scaleImages())
.pipe(gulp.dest(…))
Custom output file names
By default, gulp-scale-images
will use {basename}.{maxWidth}w-{maxHeight}h.{format}
(e.g. foo.500w-300h.jpeg
). You can define a custom logic though:
const path = require('path')
const scaleImages = require('gulp-scale-images')
const computeFileName = (output, scale, cb) => {
const fileName = [
path.basename(output.path, output.extname), // strip extension
scale.maxWidth + 'w',
scale.format || output.extname
].join('.')
cb(null, fileName)
}
gulp.src(…)
.pipe(through.obj(computeScaleInstructions))
.pipe(scaleImages(computeFileName)) // not that we pass computeFileName here
.pipe(gulp.dest(…))
gulp-scale-images
works well with
flat-map
– A flat map implementation for node streams. (One chunk in,n
chunks out.)replace-ext
– Replaces a file extension with another one.
Similar libraries
Some similar libraries and why I think this one is better.
gulp-image-resize
gulp-sharp
- is not being maintained
- has no tests
- supports only one scale instruction
gulp-retinize
gulp-imgconv
- has no tests
- supports only one scale instruction
gulp-inline-resize
gulp-unretina
gulp-gm-limit
- doesn't seem to be maintained
- supports only one scale instruction
gulp-imgresize
- no documentation
- is not being maintained
- has no tests
Contributing
If you have a question or have difficulties using gulp-scale-images
, please double-check your code and setup first. If you think you have found a bug or want to propose a feature, refer to the issues page.