BC-6431 - Fix tldraw export to image functionality

src/components/Editor.tsx

@@ -16,12 +16,19 @@ function Editor({
   focusModeHandler: (isFocusMode: boolean) => void;
 }) {
   const { onSaveProjectAs, onSaveProject, onOpenMedia } = useFileSystem();
-  const { onMount, onOpen, onAssetCreate, onAssetDelete, onPatch, ...events } =
-    useMultiplayerState({
-      roomId,
-      setIsDarkMode: darkModeHandler,
-      setIsFocusMode: focusModeHandler,
-    });
+  const {
+    onMount,
+    onOpen,
+    onAssetCreate,
+    onAssetDelete,
+    onPatch,
+    onExport,
+    ...events
+  } = useMultiplayerState({
+    roomId,
+    setIsDarkMode: darkModeHandler,
+    setIsFocusMode: focusModeHandler,
+  });
   const containerRef = useRef<HTMLDivElement | null>(null);
   useTldrawUiSanitizer(containerRef);
   const { isDarkMode } = useTldrawSettings();
@@ -42,6 +49,7 @@ function Editor({
         disableAssets={false}
         onMount={onMount}
         onPatch={onPatch}
+        onExport={onExport}
         darkMode={isDarkMode}
         {...events}
         onOpenProject={onOpen}

src/hooks/useMultiplayerState.ts

@@ -2,6 +2,7 @@ import {
   TDAsset,
   TDBinding,
   TDDocument,
+  TDExport,
   TDFile,
   TDShape,
   TDUser,
@@ -26,6 +27,7 @@ import {
 } from "../stores/setup";
 import { STORAGE_SETTINGS_KEY } from "../utils/userSettings";
 import { UserPresence } from "../types/UserPresence";
+import { getImageBlob } from "../utils/imageExportUtils";
 
 declare const window: Window & { app: TldrawApp };
 
@@ -194,6 +196,7 @@ export function useMultiplayerState({
   const onMount = useCallback(
     (app: TldrawApp) => {
       app.loadRoom(roomId);
+      app.document.name = `room-${roomId}`;
       // Turn off the app's own undo / redo stack
       app.pause();
       // Put the state into the window, for debugging
@@ -237,6 +240,20 @@ export function useMultiplayerState({
     room.updatePresence({ tdUser });
   }, []);
 
+  const onExport = useCallback(
+    async (app: TldrawApp, info: TDExport) => {
+      const blob = await getImageBlob(app, info.type);
+      if (!blob) return;
+
+      const url = URL.createObjectURL(blob);
+      const link = document.createElement("a");
+      link.href = url;
+      link.download = `${roomId}_export.${info.type}`;
+      link.click();
+    },
+    [roomId],
+  );
+
   // Document Changes --------
 
   // Update app users whenever there is a change in the room users
@@ -327,6 +344,7 @@ export function useMultiplayerState({
     onRedo,
     onMount,
     onOpen,
+    onExport,
     onChangePage,
     onChangePresence,
     loading,

src/utils/imageExportUtils.ts

@@ -0,0 +1,293 @@
+import {
+  TDExportBackground,
+  TDExportType,
+  TDShape,
+  TDShapeType,
+  TLDR,
+  TldrawApp,
+} from "@tldraw/tldraw";
+import { TLBounds, Utils } from "@tldraw/core";
+
+const SVG_EXPORT_PADDING = 16;
+
+const getImageBlob = async (
+  app: TldrawApp,
+  type: string,
+): Promise<Blob | undefined> => {
+  const format = type as TDExportType;
+  if (format === TDExportType.JSON) return;
+
+  const svg = await getSvg(app, format);
+  if (!svg) return;
+
+  if (format === TDExportType.SVG) {
+    const svgString = TLDR.getSvgString(svg, 1);
+    const blob = new Blob([svgString], { type: "image/svg+xml" });
+
+    return blob;
+  }
+
+  const imageBlob = await TLDR.getImageForSvg(svg, format, {
+    scale: 2,
+    quality: 1,
+  });
+
+  return imageBlob;
+};
+
+const getSvg = async (
+  app: TldrawApp,
+  format: TDExportType,
+): Promise<SVGElement | undefined> => {
+  // this function was mostly copied from the tldraw package
+  // as we need to extend its functionality to support exporting assets stored in s3
+
+  const ids = app.selectedIds.length
+    ? app.selectedIds
+    : Object.keys(app.page.shapes);
+
+  if (ids.length === 0) return;
+
+  const includeLocalFonts = format !== TDExportType.SVG;
+  const svg = await createInitialSvg(includeLocalFonts);
+
+  // Get the shapes in order
+  const shapes = ids
+    .map((id) => app.getShape(id, app.currentPageId))
+    .sort((a, b) => a.childIndex - b.childIndex);
+
+  // Find their common bounding box. Shapes will be positioned relative to this box
+  const commonBounds = Utils.getCommonBounds(shapes.map(TLDR.getRotatedBounds));
+
+  // Assemble the final SVG by iterating through each shape and its children
+  shapes.forEach((shape) => addShapeToSvg(svg, shape, commonBounds, app));
+
+  resizeToBoundingBox(svg, commonBounds);
+
+  removeHiddenElements(svg, commonBounds);
+
+  setBackgroundColor(svg, app);
+
+  removeUnusedElements(svg);
+
+  return svg;
+};
+
+const addShapeToSvg = (
+  svg: SVGElement,
+  shape: TDShape,
+  commonBounds: TLBounds,
+  app: TldrawApp,
+) => {
+  {
+    // The shape is a group! Just add the children.
+    if (shape.children?.length) {
+      // Create a group <g> elm for shape
+      const g = document.createElementNS("http://www.w3.org/2000/svg", "g");
+
+      // Get the shape's children as elms and add them to the group
+      shape.children.forEach((childId) => {
+        const shape = app.getShape(childId, app.currentPageId);
+        const elm = getSvgElementForShape(shape, commonBounds, app);
+
+        if (elm) {
+          g.append(elm);
+        }
+      });
+
+      // Add the group elm to the SVG
+      svg.append(g);
+
+      return;
+    }
+
+    // Just add the shape's element to the svg
+    const elm = getSvgElementForShape(shape, commonBounds, app);
+
+    if (elm) {
+      svg.append(elm);
+    }
+  }
+};
+
+const createInitialSvg = async (includeLocalFonts: boolean) => {
+  // Embed our custom fonts
+
+  const svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
+  const defs = document.createElementNS("http://www.w3.org/2000/svg", "defs");
+  const style = document.createElementNS("http://www.w3.org/2000/svg", "style");
+
+  if (typeof window !== "undefined") {
+    window.focus(); // weird but necessary
+  }
+
+  await includeTldrawFonts(includeLocalFonts, style);
+
+  defs.append(style);
+  svg.append(defs);
+
+  return svg;
+};
+
+const resizeToBoundingBox = (svg: SVGElement, commonBounds: TLBounds) => {
+  // Resize the elm to the bounding box
+
+  svg.setAttribute(
+    "viewBox",
+    [
+      0,
+      0,
+      commonBounds.width + SVG_EXPORT_PADDING * 2,
+      commonBounds.height + SVG_EXPORT_PADDING * 2,
+    ].join(" "),
+  );
+};
+
+const removeHiddenElements = (svg: SVGElement, commonBounds: TLBounds) => {
+  // Clean up the SVG by removing any hidden elements
+
+  svg.setAttribute(
+    "width",
+    (commonBounds.width + SVG_EXPORT_PADDING * 2).toString(),
+  );
+  svg.setAttribute(
+    "height",
+    (commonBounds.height + SVG_EXPORT_PADDING * 2).toString(),
+  );
+};
+
+const removeUnusedElements = (svg: SVGElement) => {
+  svg
+    .querySelectorAll(
+      ".tl-fill-hitarea, .tl-stroke-hitarea, .tl-binding-indicator",
+    )
+    .forEach((elm) => elm.remove());
+};
+
+const setBackgroundColor = (svg: SVGElement, app: TldrawApp) => {
+  // Set export background
+
+  const exportBackground: TDExportBackground = app.settings.exportBackground;
+  const darkBackground = "#212529";
+  const lightBackground = "rgb(248, 249, 250)";
+
+  switch (exportBackground) {
+    case TDExportBackground.Auto: {
+      svg.style.setProperty(
+        "background-color",
+        app.settings.isDarkMode ? darkBackground : lightBackground,
+      );
+      break;
+    }
+    case TDExportBackground.Dark: {
+      svg.style.setProperty("background-color", darkBackground);
+      break;
+    }
+    case TDExportBackground.Light: {
+      svg.style.setProperty("background-color", lightBackground);
+      break;
+    }
+    case TDExportBackground.Transparent:
+    default: {
+      svg.style.setProperty("background-color", "transparent");
+      break;
+    }
+  }
+};
+
+const getSvgElementForShape = (
+  shape: TDShape,
+  commonBounds: TLBounds,
+  app: TldrawApp,
+) => {
+  // A quick routine to get an SVG element for each shape
+
+  const util = TLDR.getShapeUtil(shape);
+  const bounds = util.getBounds(shape);
+  const elm = util.getSvgElement(shape, app.settings.isDarkMode);
+
+  if (!elm) return;
+
+  // If the element is an image, set the asset src as the xlinkhref
+  if (shape.type === TDShapeType.Image) {
+    elm.setAttribute("xlink:href", serializeImage(shape.id));
+  } else if (shape.type === TDShapeType.Video) {
+    elm.setAttribute("xlink:href", app.serializeVideo(shape.id));
+  }
+
+  // Put the element in the correct position relative to the common bounds
+  elm.setAttribute(
+    "transform",
+    `translate(${(
+      SVG_EXPORT_PADDING +
+      shape.point[0] -
+      commonBounds.minX
+    ).toFixed(2)}, ${(
+      SVG_EXPORT_PADDING +
+      shape.point[1] -
+      commonBounds.minY
+    ).toFixed(2)}) rotate(${(((shape.rotation || 0) * 180) / Math.PI).toFixed(
+      2,
+    )}, ${(bounds.width / 2).toFixed(2)}, ${(bounds.height / 2).toFixed(2)})`,
+  );
+
+  return elm;
+};
+
+const serializeImage = (id: string): string => {
+  const image = document.getElementById(id + "_image") as HTMLImageElement;
+  if (image) {
+    const canvas = document.createElement("canvas");
+    canvas.width = image.naturalWidth;
+    canvas.height = image.naturalHeight;
+    canvas.getContext("2d")!.drawImage(image, 0, 0);
+    return canvas.toDataURL("image/png");
+  } else throw new Error("Image with id " + id + " not found");
+};
+
+const includeTldrawFonts = async (
+  includeLocalFonts: boolean,
+  style: SVGElement,
+) => {
+  if (!includeLocalFonts) {
+    style.textContent = `@import url('https://fonts.googleapis.com/css2?family=Caveat+Brush&family=Source+Code+Pro&family=Source+Sans+Pro&family=Crimson+Pro&display=block');`;
+    return;
+  }
+
+  try {
+    const { fonts } = await fetch(TldrawApp.assetSrc, {
+      mode: "no-cors",
+    }).then((d) => d.json());
+
+    style.textContent = `
+          @font-face {
+            font-family: 'Caveat Brush';
+            src: url(data:application/x-font-woff;charset=utf-8;base64,${fonts.caveat}) format('woff');
+            font-weight: 500;
+            font-style: normal;
+          }
+          @font-face {
+            font-family: 'Source Code Pro';
+            src: url(data:application/x-font-woff;charset=utf-8;base64,${fonts.source_code_pro}) format('woff');
+            font-weight: 500;
+            font-style: normal;
+          }
+          @font-face {
+            font-family: 'Source Sans Pro';
+            src: url(data:application/x-font-woff;charset=utf-8;base64,${fonts.source_sans_pro}) format('woff');
+            font-weight: 500;
+            font-style: normal;
+          }
+          @font-face {
+            font-family: 'Crimson Pro';
+            src: url(data:application/x-font-woff;charset=utf-8;base64,${fonts.crimson_pro}) format('woff');
+            font-weight: 500;
+            font-style: normal;
+          }
+          `;
+  } catch (e) {
+    TLDR.warn("Could not find tldraw-assets.json file.");
+  }
+};
+
+export { getImageBlob };