feat: use upng

package.json

@@ -53,6 +53,7 @@
     "sass": "1.51.0",
     "socket.io-client": "2.3.1",
     "tunnel-rat": "0.1.2",
+    "upng-js": "2.1.0",
     "workbox-background-sync": "^6.5.4",
     "workbox-broadcast-update": "^6.5.4",
     "workbox-cacheable-response": "^6.5.4",
@@ -78,6 +79,7 @@
     "@types/react-dom": "18.0.6",
     "@types/resize-observer-browser": "0.1.7",
     "@types/socket.io-client": "1.4.36",
+    "@types/upng-js": "2.1.2",
     "chai": "4.3.6",
     "dotenv": "16.0.1",
     "eslint-config-prettier": "8.5.0",

src/data/blob.ts

@@ -13,6 +13,7 @@ import { FileSystemHandle, nativeFileSystemSupported } from "./filesystem";
 import { isValidExcalidrawData, isValidLibrary } from "./json";
 import { restore, restoreLibraryItems } from "./restore";
 import { ImportedLibraryData } from "./types";
+import UPNG from "upng-js";
 
 const parseFileContents = async (blob: Blob | File) => {
   let contents: string;
@@ -210,9 +211,7 @@ export const loadLibraryFromBlob = async (
   return parseLibraryJSON(await parseFileContents(blob), defaultStatus);
 };
 
-export const canvasToBlob = async (
-  canvas: HTMLCanvasElement,
-): Promise<Blob> => {
+const _canvasToBlob = async (canvas: HTMLCanvasElement): Promise<Blob> => {
   return new Promise((resolve, reject) => {
     try {
       canvas.toBlob((blob) => {
@@ -232,6 +231,31 @@ export const canvasToBlob = async (
   });
 };
 
+export const canvasToBlob = async (
+  canvas: HTMLCanvasElement,
+): Promise<Blob> => {
+  const ctx = canvas.getContext("2d");
+
+  if (!ctx) {
+    throw new Error("No canvas context");
+  }
+
+  console.time("getImageData");
+  const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height).data;
+  console.timeEnd("getImageData");
+
+  console.time("encode");
+  const pngData = UPNG.encode(
+    [imageData.buffer],
+    canvas.width,
+    canvas.height,
+    0,
+  );
+  console.timeEnd("encode");
+
+  return new Blob([pngData], { type: "image/png" });
+};
+
 /** generates SHA-1 digest from supplied file (if not supported, falls back
     to a 40-char base64 random id) */
 export const generateIdFromFile = async (file: File): Promise<FileId> => {

src/data/index.ts

@@ -75,7 +75,9 @@ export const exportCanvas = async (
   document.body.appendChild(tempCanvas);
 
   if (type === "png") {
+    console.time("export png");
     let blob = await canvasToBlob(tempCanvas);
+    console.timeEnd("export png");
     tempCanvas.remove();
     if (appState.exportEmbedScene) {
       blob = await (

yarn.lock

@@ -2851,6 +2851,11 @@
   resolved "https://registry.yarnpkg.com/@types/trusted-types/-/trusted-types-2.0.3.tgz#a136f83b0758698df454e328759dbd3d44555311"
   integrity sha512-NfQ4gyz38SL8sDNrSixxU2Os1a5xcdFxipAFxYEuLUlvU2uDwS4NUpsImcf1//SlWItCVMMLiylsxbmNMToV/g==
 
+"@types/upng-js@2.1.2":
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/@types/upng-js/-/upng-js-2.1.2.tgz#4680f700c3003eaf958b92418c6e19521bb1e034"
+  integrity sha512-sxCnLDEmGFDcnrdSMml3/mDSbfSAvt86Ld32J6Ac75Og7GzzmwHbUnJNTue74tfQC/3PPD/W0jG2dQuF9v6UOg==
+
 "@types/ws@^8.5.1":
   version "8.5.4"
   resolved "https://registry.yarnpkg.com/@types/ws/-/ws-8.5.4.tgz#bb10e36116d6e570dd943735f86c933c1587b8a5"
@@ -8034,7 +8039,7 @@ p-try@^2.0.0:
   resolved "https://registry.yarnpkg.com/p-try/-/p-try-2.2.0.tgz#cb2868540e313d61de58fafbe35ce9004d5540e6"
   integrity sha512-R4nPAVTAU0B9D35/Gk3uJf/7XYbQcyohSKdvAxIRSNghFl4e71hVoGnBNQz9cWaXxO2I10KTC+3jMdvvoKw6dQ==
 
-pako@1.0.11:
+pako@1.0.11, pako@^1.0.5:
   version "1.0.11"
   resolved "https://registry.yarnpkg.com/pako/-/pako-1.0.11.tgz#6c9599d340d54dfd3946380252a35705a6b992bf"
   integrity sha512-4hLB8Py4zZce5s4yd9XzopqwVv/yGNhV1Bl8NTmCq1763HeK2+EwVTv+leGeL13Dnh2wfbqowVPXCIO0z4taYw==
@@ -10557,6 +10562,13 @@ update-browserslist-db@^1.0.10:
     escalade "^3.1.1"
     picocolors "^1.0.0"
 
+upng-js@2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/upng-js/-/upng-js-2.1.0.tgz#7176e73973db361ca95d0fa14f958385db6b9dd2"
+  integrity sha512-d3xzZzpMP64YkjP5pr8gNyvBt7dLk/uGI67EctzDuVp4lCZyVMo0aJO6l/VDlgbInJYDY6cnClLoBp29eKWI6g==
+  dependencies:
+    pako "^1.0.5"
+
 uri-js@^4.2.2:
   version "4.4.1"
   resolved "https://registry.yarnpkg.com/uri-js/-/uri-js-4.4.1.tgz#9b1a52595225859e55f669d928f88c6c57f2a77e"