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https://github.com/zebrajaeger/gulp-scale-images
https://github.com/zebrajaeger/gulp-scale-images
Last synced: 9 days ago
JSON representation
- Host: GitHub
- URL: https://github.com/zebrajaeger/gulp-scale-images
- Owner: zebrajaeger
- License: isc
- Created: 2018-12-23T12:13:18.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2018-12-23T14:50:18.000Z (almost 6 years ago)
- Last Synced: 2024-10-03T06:51:03.041Z (about 1 month ago)
- Language: JavaScript
- Size: 30.3 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: license.md
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README
# gulp-scale-images
**[Gulp](https://gulpjs.com) plugin to make each image smaller. Combined with [`flat-map`](https://npmjs.com/package/flat-map), you can create multiple variantes per image**, which is useful for [responsive images](https://developer.mozilla.org/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images).
## Motivation
This is 'heavily inspired' by gulp-scale-images (https://www.npmjs.com/package/gulp-scale-images). And the lib does a great job.
So why fork this?
On my Orange and Raspberry Pi, the Sharp-Code node crashes because of memory errors and i did not found a workaround.
So i decided to take the plugin and separate the parts (Gulp plugin and resizer).
Now there is a unique interface and you can decide to use sharp or jimp as resizing engine.
## Installing
```shell
npm install @zebrajaeger/gulp-scale-images @zebrajaeger/gulp-scale-images-resize-sharp --save-dev
```
or
```shell
npm install @zebrajaeger/gulp-scale-images @zebrajaeger/gulp-scale-images-resize-jimp --save-dev
```
## Usage
`gulp-scale-images` expects the instructions for each file to be in `file.scale`. They may look like this:
```js
{
maxWidth: 300, // optional maximum width, respecting the aspect ratio
maxHeight: 400, // optional maximum height, respecting the aspect ratio
format: 'jpeg', // optional, one of ('jpeg', 'png', 'webp')
quality: 80, // optional and only for jpeg target format
withoutEnlargement: false // optional, default is true
}
```
*Note*: You must specify at least one of `maxWidth` and `maxHeight`.
An example, we're going to generate *two* smaller variants for each input file. We're going to use [`flat-map`](https://npmjs.com/package/flat-map) for this:
```js
const gulp = require('gulp')
const flatMap = require('flat-map').default
const scaleImages = require('@zebrajaeger/gulp-scale-images')
// choose one of them
const scaleImagesResize = require('@zebrajaeger/gulp-scale-images-resize-sharp')
const scaleImagesResize = require('@zebrajaeger/gulp-scale-images-resize-jimp')
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(scaleImagesResize))
.pipe(gulp.dest(…))
```
### 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:
```js
const readMetadata = require('gulp-scale-images/read-metadata')
const through = require('through2')
const scaleImages = require('@zebrajaeger/gulp-scale-images')
// choose one of them
const scaleImagesResize = require('@zebrajaeger/gulp-scale-images-resize-sharp')
const scaleImagesResize = require('@zebrajaeger/gulp-scale-images-resize-jimp')
const computeScaleInstructions = (file, _, cb) => {
readMetadata(file.path, (err, meta) => {
if (err) return cb(err)
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(scaleImagesResize))
.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:
```js
const path = require('path')
const scaleImages = require('@zebrajaeger/gulp-scale-images')
// choose one of them
const scaleImagesResize = require('@zebrajaeger/gulp-scale-images-resize-sharp')
const scaleImagesResize = require('@zebrajaeger/gulp-scale-images-resize-jimp')
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(scaleImagesResize, computeFileName)) // not that we pass computeFileName here
.pipe(gulp.dest(…))
```
### `gulp-scale-images` works well with
- [`flat-map`](https://www.npmjs.com/package/flat-map) – A flat map implementation for node streams. (One chunk in, `n` chunks out.)
- [`replace-ext`](https://www.npmjs.com/package/replace-ext) – Replaces a file extension with another one.
## 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](https://github.com/zebrajaeger/gulp-scale-images/issues).