refact(workers): split encode-core

src/services/encode-core.js

@@ -1,84 +0,0 @@
-import EventEmitter from 'eventemitter3'
-
-import {
-  GifWriter,
-  MedianCutColorReducer,
-  IndexedColorImage
-} from 'gif-writer'
-
-import { boomerang } from '/services/effects.js'
-import { pipe, calcProgress } from '/services/util.js'
-
-class OutputStream {
-  constructor () {
-    this.buffer = []
-  }
-
-  writeByte (b) {
-    this.buffer.push(b)
-  }
-
-  writeBytes (bb) {
-    Array.prototype.push.apply(this.buffer, bb)
-  }
-}
-
-export function write (imageWidth, imageHeight, delay, indexedColorImages, boomerangEffect = false) {
-  const emitter = new EventEmitter()
-
-  // yup, this is the browser nextTick implementation we are waiting for :facepalm:
-  Promise.resolve().then(() => {
-    emitter.emit('progress', 0)
-
-    const outputStream = new OutputStream()
-    const writer = new GifWriter(outputStream)
-
-    writer.writeHeader()
-
-    writer.writeLogicalScreenInfo({
-      width: imageWidth,
-      height: imageHeight
-    })
-
-    writer.writeLoopControlInfo(0)
-
-    const frames = pipe(indexedColorImages, [
-      (images) => boomerangEffect ? boomerang(images) : images
-    ])
-
-    frames.forEach((indexedColorImage, index, { length }) => {
-      writer.writeTableBasedImageWithGraphicControl(indexedColorImage, { delayTimeInMS: delay })
-      emitter.emit('progress', calcProgress(0, 0.99, (index + 1) / length))
-    })
-
-    writer.writeTrailer()
-    emitter.emit('progress', 1)
-
-    emitter.emit('done', outputStream.buffer)
-  })
-
-  return emitter
-}
-
-export function convertImageDataToIndexedColorImage (imageData, paletteSize) {
-  const reducer = new MedianCutColorReducer(imageData, paletteSize)
-
-  const paletteData = reducer.process()
-
-  const data = Array.from(imageData.data)
-  const indexedColorImageData = []
-
-  for (let index = 0, length = data.length; index < length; index += 4) {
-    const [r, g, b] = data.slice(index, index + 4) // r,g,b,a
-    indexedColorImageData.push(reducer.map(r, g, b))
-  }
-
-  return new IndexedColorImage(
-    {
-      width: imageData.width,
-      height: imageData.height
-    },
-    indexedColorImageData,
-    paletteData
-  )
-}

src/services/quantize-color.js

@@ -0,0 +1,27 @@
+import {
+  MedianCutColorReducer,
+  IndexedColorImage
+} from 'gif-writer'
+
+export function convertImageDataToIndexedColorImage (imageData, paletteSize) {
+  const reducer = new MedianCutColorReducer(imageData, paletteSize)
+
+  const paletteData = reducer.process()
+
+  const data = Array.from(imageData.data)
+  const indexedColorImageData = []
+
+  for (let index = 0, length = data.length; index < length; index += 4) {
+    const [r, g, b] = data.slice(index, index + 4) // r,g,b,a
+    indexedColorImageData.push(reducer.map(r, g, b))
+  }
+
+  return new IndexedColorImage(
+    {
+      width: imageData.width,
+      height: imageData.height
+    },
+    indexedColorImageData,
+    paletteData
+  )
+}

src/services/quantize-color.worker.js

@@ -1,11 +1,7 @@
-import { convertImageDataToIndexedColorImage } from '/services/encode-core.js'
+import { convertImageDataToIndexedColorImage } from '/services/quantize-color.js'
 
-onmessage = handleMessage
+onmessage = event => {
-
-function handleMessage (event) {
   const { imageData, paletteSize } = event.data
 
-  const indexedColorImage = convertImageDataToIndexedColorImage(imageData, paletteSize)
+  postMessage(convertImageDataToIndexedColorImage(imageData, paletteSize))
-
-  postMessage(indexedColorImage)
 }

src/services/write-gif.js

@@ -0,0 +1,46 @@
+import { GifWriter } from 'gif-writer'
+import { boomerang } from '/services/effects.js'
+import { pipe, calcProgress } from '/services/util.js'
+
+class OutputStream {
+  constructor () {
+    this.buffer = []
+  }
+
+  writeByte (b) {
+    this.buffer.push(b)
+  }
+
+  writeBytes (bb) {
+    Array.prototype.push.apply(this.buffer, bb)
+  }
+}
+
+export function write (imageWidth, imageHeight, delay, indexedColorImages, boomerangEffect, progressCallback) {
+  const outputStream = new OutputStream()
+  const writer = new GifWriter(outputStream)
+
+  progressCallback(0)
+  writer.writeHeader()
+
+  writer.writeLogicalScreenInfo({
+    width: imageWidth,
+    height: imageHeight
+  })
+
+  writer.writeLoopControlInfo(0)
+
+  const frames = pipe(indexedColorImages, [
+    (images) => boomerangEffect ? boomerang(images) : images
+  ])
+
+  frames.forEach((indexedColorImage, index, { length }) => {
+    writer.writeTableBasedImageWithGraphicControl(indexedColorImage, { delayTimeInMS: delay })
+    progressCallback(calcProgress(0, 0.99, (index + 1) / length))
+  })
+
+  writer.writeTrailer()
+  progressCallback(1)
+
+  return outputStream.buffer
+}

src/services/write-gif.worker.js

@@ -1,23 +1,19 @@
-import { write } from '/services/encode-core.js'
+import { write } from '/services/write-gif.js'
 
-onmessage = handleMessage
+const postProgressMessage = value => postMessage({ type: 'progress', payload: { value } })
+const postDoneMessage = buffer => postMessage({ type: 'done', payload: { buffer } })
 
-async function handleMessage (event) {
+onmessage = event => {
   const { imageWidth, imageHeight, delayTime, indexedColorImages, boomerangEffect } = event.data
 
-  const writing = write(imageWidth, imageHeight, delayTime, indexedColorImages, boomerangEffect)
+  const buffer = write(
+    imageWidth,
+    imageHeight,
+    delayTime,
+    indexedColorImages,
+    boomerangEffect,
+    postProgressMessage
+  )
 
-  writing.on('progress', value => postMessage({
+  postDoneMessage(buffer)
-    type: 'progress',
-    payload: {
-      value
-    }
-  }))
-
-  writing.once('done', buffer => postMessage({
-    type: 'done',
-    payload: {
-      buffer
-    }
-  }))
 }