refactor: separate elements logic into a standalone package (#9285)

packages/element/src/image.ts

@@ -0,0 +1,153 @@
+// -----------------------------------------------------------------------------
+// ExcalidrawImageElement & related helpers
+// -----------------------------------------------------------------------------
+
+import { MIME_TYPES, SVG_NS } from "@excalidraw/common";
+
+import type {
+  AppClassProperties,
+  DataURL,
+  BinaryFiles,
+} from "@excalidraw/excalidraw/types";
+
+import { isInitializedImageElement } from "./typeChecks";
+
+import type {
+  ExcalidrawElement,
+  FileId,
+  InitializedExcalidrawImageElement,
+} from "./types";
+
+export const loadHTMLImageElement = (dataURL: DataURL) => {
+  return new Promise<HTMLImageElement>((resolve, reject) => {
+    const image = new Image();
+    image.onload = () => {
+      resolve(image);
+    };
+    image.onerror = (error) => {
+      reject(error);
+    };
+    image.src = dataURL;
+  });
+};
+
+/** NOTE: updates cache even if already populated with given image. Thus,
+ * you should filter out the images upstream if you want to optimize this. */
+export const updateImageCache = async ({
+  fileIds,
+  files,
+  imageCache,
+}: {
+  fileIds: FileId[];
+  files: BinaryFiles;
+  imageCache: AppClassProperties["imageCache"];
+}) => {
+  const updatedFiles = new Map<FileId, true>();
+  const erroredFiles = new Map<FileId, true>();
+
+  await Promise.all(
+    fileIds.reduce((promises, fileId) => {
+      const fileData = files[fileId as string];
+      if (fileData && !updatedFiles.has(fileId)) {
+        updatedFiles.set(fileId, true);
+        return promises.concat(
+          (async () => {
+            try {
+              if (fileData.mimeType === MIME_TYPES.binary) {
+                throw new Error("Only images can be added to ImageCache");
+              }
+
+              const imagePromise = loadHTMLImageElement(fileData.dataURL);
+              const data = {
+                image: imagePromise,
+                mimeType: fileData.mimeType,
+              } as const;
+              // store the promise immediately to indicate there's an in-progress
+              // initialization
+              imageCache.set(fileId, data);
+
+              const image = await imagePromise;
+
+              imageCache.set(fileId, { ...data, image });
+            } catch (error: any) {
+              erroredFiles.set(fileId, true);
+            }
+          })(),
+        );
+      }
+      return promises;
+    }, [] as Promise<any>[]),
+  );
+
+  return {
+    imageCache,
+    /** includes errored files because they cache was updated nonetheless */
+    updatedFiles,
+    /** files that failed when creating HTMLImageElement */
+    erroredFiles,
+  };
+};
+
+export const getInitializedImageElements = (
+  elements: readonly ExcalidrawElement[],
+) =>
+  elements.filter((element) =>
+    isInitializedImageElement(element),
+  ) as InitializedExcalidrawImageElement[];
+
+export const isHTMLSVGElement = (node: Node | null): node is SVGElement => {
+  // lower-casing due to XML/HTML convention differences
+  // https://johnresig.com/blog/nodename-case-sensitivity
+  return node?.nodeName.toLowerCase() === "svg";
+};
+
+export const normalizeSVG = (SVGString: string) => {
+  const doc = new DOMParser().parseFromString(SVGString, MIME_TYPES.svg);
+  const svg = doc.querySelector("svg");
+  const errorNode = doc.querySelector("parsererror");
+  if (errorNode || !isHTMLSVGElement(svg)) {
+    throw new Error("Invalid SVG");
+  } else {
+    if (!svg.hasAttribute("xmlns")) {
+      svg.setAttribute("xmlns", SVG_NS);
+    }
+
+    let width = svg.getAttribute("width");
+    let height = svg.getAttribute("height");
+
+    // Do not use % or auto values for width/height
+    // to avoid scaling issues when rendering at different sizes/zoom levels
+    if (width?.includes("%") || width === "auto") {
+      width = null;
+    }
+    if (height?.includes("%") || height === "auto") {
+      height = null;
+    }
+
+    const viewBox = svg.getAttribute("viewBox");
+
+    if (!width || !height) {
+      width = width || "50";
+      height = height || "50";
+
+      if (viewBox) {
+        const match = viewBox.match(
+          /\d+ +\d+ +(\d+(?:\.\d+)?) +(\d+(?:\.\d+)?)/,
+        );
+        if (match) {
+          [, width, height] = match;
+        }
+      }
+
+      svg.setAttribute("width", width);
+      svg.setAttribute("height", height);
+    }
+
+    // Make sure viewBox is set
+    if (!viewBox) {
+      svg.setAttribute("viewBox", `0 0 ${width} ${height}`);
+    }
+
+    return svg.outerHTML;
+  }
+};