feat: resave to png/svg with metadata if you loaded your scene from a png/svg file (#3645)

Co-authored-by: dwelle <luzar.david@gmail.com>

src/data/resave.ts

@@ -0,0 +1,38 @@
+import { ExcalidrawElement } from "../element/types";
+import { AppState } from "../types";
+import { exportCanvas } from ".";
+import { getNonDeletedElements } from "../element";
+import { getFileHandleType, isImageFileHandleType } from "./blob";
+
+export const resaveAsImageWithScene = async (
+  elements: readonly ExcalidrawElement[],
+  appState: AppState,
+) => {
+  const { exportBackground, viewBackgroundColor, name, fileHandle } = appState;
+
+  const fileHandleType = getFileHandleType(fileHandle);
+
+  if (!fileHandle || !isImageFileHandleType(fileHandleType)) {
+    throw new Error(
+      "fileHandle should exist and should be of type svg or png when resaving",
+    );
+  }
+  appState = {
+    ...appState,
+    exportEmbedScene: true,
+  };
+
+  await exportCanvas(
+    fileHandleType,
+    getNonDeletedElements(elements),
+    appState,
+    {
+      exportBackground,
+      viewBackgroundColor,
+      name,
+      fileHandle,
+    },
+  );
+
+  return { fileHandle };
+};