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/**
*
* @copyright Copyright (c) 2020, Daniel Calviño Sánchez (danxuliu@gmail.com)
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
import { generateFilePath } from '@nextcloud/router'
let worker
const pendingResults = {}
let pendingResultsNextId = 0
function loadWorker() {
try {
worker = new Worker(generateFilePath('spreed', '', 'js/image-blurrer-worker.js'))
worker.onmessage = function(message) {
const pendingResult = pendingResults[message.data.id]
if (!pendingResult) {
console.debug('No pending result for blurring image with id ' + message.data.id)
return
}
pendingResult(message.data.blurredImageAsDataUrl)
delete pendingResults[message.data.id]
}
} catch (exception) {
worker = null
console.error('Image blurrer worker could not be loaded', exception)
}
}
function blurSync(image, width, height, blurRadius) {
return new Promise((resolve, reject) => {
const canvas = document.createElement('canvas')
canvas.width = width
canvas.height = height
const context = canvas.getContext('2d')
context.filter = `blur(${blurRadius}px)`
context.drawImage(image, 0, 0, canvas.width, canvas.height)
resolve(canvas.toDataURL())
})
}
export default function blur(image, width, height, blurRadius) {
if (typeof OffscreenCanvas === 'undefined') {
return blurSync(image, width, height, blurRadius)
}
if (worker === undefined) {
loadWorker()
}
if (!worker) {
return blurSync(image, width, height, blurRadius)
}
const id = pendingResultsNextId
pendingResultsNextId++
return new Promise((resolve, reject) => {
pendingResults[id] = resolve
worker.postMessage({
id: id,
image: image,
width: width,
height: height,
blurRadius: blurRadius,
})
})
}
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