/
index.js
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/
index.js
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'use strict'
const path = require('path')
const graphicsMagick = require('gm')
module.exports = class ImageminGm {
constructor (gmPath) {
this.gm = gmPath
// Add trailing separator ('/' on Posix, '\\' on Windows)
? graphicsMagick.subClass({ appPath: path.normalize(gmPath + path.sep) })
: graphicsMagick
}
resize (opts) {
return buf => {
opts = Object.assign({}, opts)
if (!Buffer.isBuffer(buf)) {
return Promise.reject(new TypeError('Expected a buffer'))
}
let image = this.gm(buf).resize(opts.width, opts.height)
if (opts.gravity) {
image = image.gravity(opts.gravity)
}
return new Promise((resolve, reject) =>
image.toBuffer((err, buffer) => (err) ? reject(err) : resolve(buffer)))
}
}
convert (to) {
return buf => {
if (!Buffer.isBuffer(buf)) {
return Promise.reject(new TypeError('Expected a buffer'))
}
to = to.replace(/jpeg/i, 'JPG').toUpperCase()
return new Promise((resolve, reject) => {
let image = this.gm(buf)
image.format({ bufferStream: true }, (err, format) => {
if (err) {
return reject(err)
}
if (format === to) {
return resolve(buf)
}
// Make sure transparent PNGs get a white background when converted to JPG
if (format === 'JPG') {
image = image
// Compression level is adjusted later in the process
.quality(100)
.background('#ffffff')
.flatten()
}
image.toBuffer(to, (err, buffer) => (err) ? reject(err) : resolve(buffer))
})
})
}
}
}