Build preprocessor pipeline

cli/src/codecs.js

@@ -30,11 +30,71 @@ import * as oxipng from "../../codecs/oxipng/pkg/squoosh_oxipng.js";
 import oxipngWasm from "asset-url:../../codecs/oxipng/pkg/squoosh_oxipng_bg.wasm";
 const oxipngPromise = oxipng.default(fsp.readFile(pathify(oxipngWasm)));
 
+import * as resize from "../../codecs/resize/pkg/squoosh_resize.js";
+import resizeWasm from "asset-url:../../codecs/resize/pkg/squoosh_resize_bg.wasm";
+const resizePromise = resize.default(fsp.readFile(pathify(resizeWasm)));
+
 // Our decoders currently rely on a `ImageData` global.
 import ImageData from "./image_data.js";
 globalThis.ImageData = ImageData;
 
-export default {
+function resizeNameToIndex(name) {
+  switch (name) {
+    case "triangle":
+      return 0;
+    case "catrom":
+      return 1;
+    case "mitchell":
+      return 2;
+    case "lanczos3":
+      return 3;
+    default:
+      throw Error(`Unknown resize algorithm "${name}"`);
+  }
+}
+
+export const preprocessors = {
+  resize: {
+    name: "Resize",
+    description: "Resize the image before compressing",
+    instantiate: async () => {
+      await resizePromise;
+      return (
+        buffer,
+        input_width,
+        input_height,
+        { width, height, method, premultiply, linearRGB }
+      ) =>
+        new ImageData(
+          resize.resize(
+            buffer,
+            input_width,
+            input_height,
+            width,
+            height,
+            resizeNameToIndex(method),
+            premultiply,
+            linearRGB
+          ),
+          width,
+          height
+        );
+    },
+    defaultOptions: {
+      // Width and height will always default to the image size.
+      // This is set elsewhere.
+      width: 1,
+      height: 1,
+      // This will be set to 'vector' if the input is SVG.
+      method: "lanczos3",
+      fitMethod: "stretch",
+      premultiply: true,
+      linearRGB: true
+    }
+  }
+};
+
+export const codecs = {
   mozjpeg: {
     name: "MozJPEG",
     extension: "jpg",

cli/src/index.js

@@ -8,7 +8,7 @@ import { version } from "json:../package.json";
 import ora from 'ora';
 import kleur from 'kleur';
 
-import supportedFormats from "./codecs.js";
+import {codecs as supportedFormats, preprocessors} from "./codecs.js";
 import WorkerPool from "./worker_pool.js";
 import { autoOptimize } from "./auto-optimizer.js";
 
@@ -47,6 +47,16 @@ async function decodeFile(file) {
   };
 }
 
+async function preprocessImage({
+	preprocessorName,
+	options,
+	file
+}) {
+	const preprocessor = await preprocessors[preprocessorName].instantiate();
+	file.bitmap= await preprocessor(file.bitmap.data, file.bitmap.width, file.bitmap.height, options);
+	return file;
+}
+
 async function encodeFile({
   file,
   size,
@@ -110,12 +120,16 @@ async function encodeFile({
 // both decoding and encoding go through the worker pool
 function handleJob(params) {
   const { operation } = params;
-  if (operation === 'encode') {
+	switch(operation) {
+		case "encode":
     return encodeFile(params);
-  }
-  if (operation === 'decode') {
+		case "decode":
     return decodeFile(params.file);
-  }
+		case "preprocess":
+			return preprocessImage(params);
+		default:
+			throw Error(`Invalid job "${operation}"`);
+	}
 }
 
 function progressTracker(results) {
@@ -175,7 +189,7 @@ async function processFiles(files) {
   await fsp.mkdir(program.outputDir, { recursive: true });
 
   let decoded = 0;
-  const decodedFiles = await Promise.all(files.map(async file => {
+  let decodedFiles = await Promise.all(files.map(async file => {
     const result = await workerPool.dispatchJob({ operation: 'decode', file });
     results.set(file, {
       file: result.file,
@@ -186,6 +200,31 @@ async function processFiles(files) {
     return result;
   }));
 
+	for (const [preprocessorName, value] of Object.entries(preprocessors)) {
+		if(!program[preprocessorName]) {
+			continue;
+		}
+		  const preprocessorParam = program[preprocessorName];
+		const preprocessorOptions = Object.assign(
+              {},
+              value.defaultOptions,
+              JSON5.parse(preprocessorParam)
+		);
+
+		decodedFiles = await Promise.all(decodedFiles.map(async file => {
+			return workerPool.dispatchJob({
+				file,
+				operation: "preprocess",
+				preprocessorName,
+				options: preprocessorOptions
+			});
+		}));
+	
+	  for (const { file, bitmap, size } of decodedFiles) {
+		
+	  }
+	}
+
   progress.progressOffset = decoded;
   progress.setStatus('Encoding ' + kleur.dim(`(${parallelism} threads)`));
   progress.setProgress(0, files.length);
@@ -261,6 +300,13 @@ if (isMainThread) {
     )
     .action(processFiles);
 
+  // Create a CLI option for each supported preprocessor
+  for (const [key, value] of Object.entries(preprocessors)) {
+    program.option(
+      `--${key} [config]`,
+	  value.description
+    );
+  }
   // Create a CLI option for each supported encoder
   for (const [key, value] of Object.entries(supportedFormats)) {
     program.option(