fix: emitted visible scene bounds not accounting for offsets (#7450)

excalidraw-app/app_constants.ts

@@ -20,9 +20,12 @@ export const WS_EVENTS = {
 } as const;
 
 export enum WS_SUBTYPES {
+  INVALID_RESPONSE = "INVALID_RESPONSE",
   INIT = "SCENE_INIT",
   UPDATE = "SCENE_UPDATE",
-  USER_VIEWPORT_BOUNDS = "USER_VIEWPORT_BOUNDS",
+  MOUSE_LOCATION = "MOUSE_LOCATION",
+  IDLE_STATUS = "IDLE_STATUS",
+  USER_VISIBLE_SCENE_BOUNDS = "USER_VISIBLE_SCENE_BOUNDS",
 }
 
 export const FIREBASE_STORAGE_PREFIXES = {

excalidraw-app/collab/Collab.tsx

@@ -18,10 +18,10 @@ import {
 } from "../../packages/excalidraw/index";
 import { Collaborator, Gesture } from "../../packages/excalidraw/types";
 import {
+  assertNever,
   preventUnload,
   resolvablePromise,
   throttleRAF,
-  viewportCoordsToSceneCoords,
   withBatchedUpdates,
 } from "../../packages/excalidraw/utils";
 import {
@@ -81,7 +81,8 @@ import { resetBrowserStateVersions } from "../data/tabSync";
 import { LocalData } from "../data/LocalData";
 import { atom, useAtom } from "jotai";
 import { appJotaiStore } from "../app-jotai";
-import { Mutable } from "../../packages/excalidraw/utility-types";
+import { Mutable, ValueOf } from "../../packages/excalidraw/utility-types";
+import { getVisibleSceneBounds } from "../../packages/excalidraw/element/bounds";
 
 export const collabAPIAtom = atom<CollabAPI | null>(null);
 export const collabDialogShownAtom = atom(false);
@@ -174,7 +175,7 @@ class Collab extends PureComponent<Props, CollabState> {
       this.portal.socket && this.portal.broadcastUserFollowed(payload);
     });
     const throttledRelayUserViewportBounds = throttleRAF(
-      this.relayUserViewportBounds,
+      this.relayVisibleSceneBounds,
     );
     const unsubOnScrollChange = this.excalidrawAPI.onScrollChange(() =>
       throttledRelayUserViewportBounds(),
@@ -384,7 +385,7 @@ class Collab extends PureComponent<Props, CollabState> {
     iv: Uint8Array,
     encryptedData: ArrayBuffer,
     decryptionKey: string,
-  ) => {
+  ): Promise<ValueOf<SocketUpdateDataSource>> => {
     try {
       const decrypted = await decryptData(iv, encryptedData, decryptionKey);
 
@@ -396,7 +397,7 @@ class Collab extends PureComponent<Props, CollabState> {
       window.alert(t("alerts.decryptFailed"));
       console.error(error);
       return {
-        type: "INVALID_RESPONSE",
+        type: WS_SUBTYPES.INVALID_RESPONSE,
       };
     }
   };
@@ -512,7 +513,7 @@ class Collab extends PureComponent<Props, CollabState> {
         );
 
         switch (decryptedData.type) {
-          case "INVALID_RESPONSE":
+          case WS_SUBTYPES.INVALID_RESPONSE:
             return;
           case WS_SUBTYPES.INIT: {
             if (!this.portal.socketInitialized) {
@@ -535,7 +536,7 @@ class Collab extends PureComponent<Props, CollabState> {
               this.reconcileElements(decryptedData.payload.elements),
             );
             break;
-          case "MOUSE_LOCATION": {
+          case WS_SUBTYPES.MOUSE_LOCATION: {
             const { pointer, button, username, selectedElementIds } =
               decryptedData.payload;
 
@@ -554,8 +555,8 @@ class Collab extends PureComponent<Props, CollabState> {
             break;
           }
 
-          case WS_SUBTYPES.USER_VIEWPORT_BOUNDS: {
-            const { bounds, socketId } = decryptedData.payload;
+          case WS_SUBTYPES.USER_VISIBLE_SCENE_BOUNDS: {
+            const { sceneBounds, socketId } = decryptedData.payload;
 
             const appState = this.excalidrawAPI.getAppState();
 
@@ -579,7 +580,7 @@ class Collab extends PureComponent<Props, CollabState> {
             this.excalidrawAPI.updateScene({
               appState: zoomToFitBounds({
                 appState,
-                bounds,
+                bounds: sceneBounds,
                 fitToViewport: true,
                 viewportZoomFactor: 1,
               }).appState,
@@ -588,7 +589,7 @@ class Collab extends PureComponent<Props, CollabState> {
             break;
           }
 
-          case "IDLE_STATUS": {
+          case WS_SUBTYPES.IDLE_STATUS: {
             const { userState, socketId, username } = decryptedData.payload;
             this.updateCollaborator(socketId, {
               userState,
@@ -596,6 +597,10 @@ class Collab extends PureComponent<Props, CollabState> {
             });
             break;
           }
+
+          default: {
+            assertNever(decryptedData, null);
+          }
         }
       },
     );
@@ -618,7 +623,7 @@ class Collab extends PureComponent<Props, CollabState> {
           appState: { followedBy: new Set(followedBy) },
         });
 
-        this.relayUserViewportBounds({ shouldPerform: true });
+        this.relayVisibleSceneBounds({ force: true });
       },
     );
 
@@ -848,25 +853,14 @@ class Collab extends PureComponent<Props, CollabState> {
     CURSOR_SYNC_TIMEOUT,
   );
 
-  relayUserViewportBounds = (props?: { shouldPerform: boolean }) => {
+  relayVisibleSceneBounds = (props?: { force: boolean }) => {
     const appState = this.excalidrawAPI.getAppState();
 
-    if (
-      this.portal.socket &&
-      (appState.followedBy.size > 0 || props?.shouldPerform)
-    ) {
-      const { x: x1, y: y1 } = viewportCoordsToSceneCoords(
-        { clientX: 0, clientY: 0 },
-        appState,
-      );
-
-      const { x: x2, y: y2 } = viewportCoordsToSceneCoords(
-        { clientX: appState.width, clientY: appState.height },
-        appState,
-      );
-
-      this.portal.broadcastUserViewportBounds(
-        { bounds: [x1, y1, x2, y2] },
+    if (this.portal.socket && (appState.followedBy.size > 0 || props?.force)) {
+      this.portal.broadcastVisibleSceneBounds(
+        {
+          sceneBounds: getVisibleSceneBounds(appState),
+        },
         `follow@${this.portal.socket.id}`,
       );
     }

excalidraw-app/collab/Portal.tsx

@@ -184,7 +184,7 @@ class Portal {
   broadcastIdleChange = (userState: UserIdleState) => {
     if (this.socket?.id) {
       const data: SocketUpdateDataSource["IDLE_STATUS"] = {
-        type: "IDLE_STATUS",
+        type: WS_SUBTYPES.IDLE_STATUS,
         payload: {
           socketId: this.socket.id,
           userState,
@@ -204,7 +204,7 @@ class Portal {
   }) => {
     if (this.socket?.id) {
       const data: SocketUpdateDataSource["MOUSE_LOCATION"] = {
-        type: "MOUSE_LOCATION",
+        type: WS_SUBTYPES.MOUSE_LOCATION,
         payload: {
           socketId: this.socket.id,
           pointer: payload.pointer,
@@ -222,19 +222,19 @@ class Portal {
     }
   };
 
-  broadcastUserViewportBounds = (
+  broadcastVisibleSceneBounds = (
     payload: {
-      bounds: [number, number, number, number];
+      sceneBounds: SocketUpdateDataSource["USER_VISIBLE_SCENE_BOUNDS"]["payload"]["sceneBounds"];
     },
     roomId: string,
   ) => {
     if (this.socket?.id) {
-      const data: SocketUpdateDataSource["USER_VIEWPORT_BOUNDS"] = {
-        type: WS_SUBTYPES.USER_VIEWPORT_BOUNDS,
+      const data: SocketUpdateDataSource["USER_VISIBLE_SCENE_BOUNDS"] = {
+        type: WS_SUBTYPES.USER_VISIBLE_SCENE_BOUNDS,
         payload: {
           socketId: this.socket.id,
           username: this.collab.state.username,
-          bounds: payload.bounds,
+          sceneBounds: payload.sceneBounds,
         },
       };
 

excalidraw-app/data/index.ts

@@ -10,6 +10,7 @@ import {
 import { serializeAsJSON } from "../../packages/excalidraw/data/json";
 import { restore } from "../../packages/excalidraw/data/restore";
 import { ImportedDataState } from "../../packages/excalidraw/data/types";
+import { SceneBounds } from "../../packages/excalidraw/element/bounds";
 import { isInvisiblySmallElement } from "../../packages/excalidraw/element/sizeHelpers";
 import { isInitializedImageElement } from "../../packages/excalidraw/element/typeChecks";
 import {
@@ -28,6 +29,7 @@ import {
   DELETED_ELEMENT_TIMEOUT,
   FILE_UPLOAD_MAX_BYTES,
   ROOM_ID_BYTES,
+  WS_SUBTYPES,
 } from "../app_constants";
 import { encodeFilesForUpload } from "./FileManager";
 import { saveFilesToFirebase } from "./firebase";
@@ -97,20 +99,23 @@ export type EncryptedData = {
 };
 
 export type SocketUpdateDataSource = {
+  INVALID_RESPONSE: {
+    type: WS_SUBTYPES.INVALID_RESPONSE;
+  };
   SCENE_INIT: {
-    type: "SCENE_INIT";
+    type: WS_SUBTYPES.INIT;
     payload: {
       elements: readonly ExcalidrawElement[];
     };
   };
   SCENE_UPDATE: {
-    type: "SCENE_UPDATE";
+    type: WS_SUBTYPES.UPDATE;
     payload: {
       elements: readonly ExcalidrawElement[];
     };
   };
   MOUSE_LOCATION: {
-    type: "MOUSE_LOCATION";
+    type: WS_SUBTYPES.MOUSE_LOCATION;
     payload: {
       socketId: string;
       pointer: { x: number; y: number; tool: "pointer" | "laser" };
@@ -119,16 +124,16 @@ export type SocketUpdateDataSource = {
       username: string;
     };
   };
-  USER_VIEWPORT_BOUNDS: {
-    type: "USER_VIEWPORT_BOUNDS";
+  USER_VISIBLE_SCENE_BOUNDS: {
+    type: WS_SUBTYPES.USER_VISIBLE_SCENE_BOUNDS;
     payload: {
       socketId: string;
       username: string;
-      bounds: [number, number, number, number];
+      sceneBounds: SceneBounds;
     };
   };
   IDLE_STATUS: {
-    type: "IDLE_STATUS";
+    type: WS_SUBTYPES.IDLE_STATUS;
     payload: {
       socketId: string;
       userState: UserIdleState;
@@ -138,10 +143,7 @@ export type SocketUpdateDataSource = {
 };
 
 export type SocketUpdateDataIncoming =
-  | SocketUpdateDataSource[keyof SocketUpdateDataSource]
-  | {
-      type: "INVALID_RESPONSE";
-    };
+  SocketUpdateDataSource[keyof SocketUpdateDataSource];
 
 export type SocketUpdateData =
   SocketUpdateDataSource[keyof SocketUpdateDataSource] & {

packages/excalidraw/CHANGELOG.md

@@ -13,6 +13,8 @@ Please add the latest change on the top under the correct section.
 
 ## Unreleased
 
+- Expose `getVisibleSceneBounds` helper to get scene bounds of visible canvas area. [#7450](https://github.com/excalidraw/excalidraw/pull/7450)
+
 ### Breaking Changes
 
 - `appState.openDialog` type was changed from `null | string` to `null | { name: string }`. [#7336](https://github.com/excalidraw/excalidraw/pull/7336)

packages/excalidraw/actions/actionCanvas.tsx

@@ -20,7 +20,7 @@ import {
   isHandToolActive,
 } from "../appState";
 import { DEFAULT_CANVAS_BACKGROUND_PICKS } from "../colors";
-import { Bounds } from "../element/bounds";
+import { SceneBounds } from "../element/bounds";
 import { setCursor } from "../cursor";
 
 export const actionChangeViewBackgroundColor = register({
@@ -211,7 +211,7 @@ export const actionResetZoom = register({
 });
 
 const zoomValueToFitBoundsOnViewport = (
-  bounds: Bounds,
+  bounds: SceneBounds,
   viewportDimensions: { width: number; height: number },
 ) => {
   const [x1, y1, x2, y2] = bounds;
@@ -235,7 +235,7 @@ export const zoomToFitBounds = ({
   fitToViewport = false,
   viewportZoomFactor = 0.7,
 }: {
-  bounds: readonly [number, number, number, number];
+  bounds: SceneBounds;
   appState: Readonly<AppState>;
   /** whether to fit content to viewport (beyond >100%) */
   fitToViewport: boolean;

packages/excalidraw/element/bounds.ts

@@ -9,7 +9,7 @@ import {
 import { distance2d, rotate, rotatePoint } from "../math";
 import rough from "roughjs/bin/rough";
 import { Drawable, Op } from "roughjs/bin/core";
-import { Point } from "../types";
+import { AppState, Point } from "../types";
 import { generateRoughOptions } from "../scene/Shape";
 import {
   isArrowElement,
@@ -35,7 +35,9 @@ export type RectangleBox = {
 
 type MaybeQuadraticSolution = [number | null, number | null] | false;
 
-// x and y position of top left corner, x and y position of bottom right corner
+/**
+ * x and y position of top left corner, x and y position of bottom right corner
+ */
 export type Bounds = readonly [
   minX: number,
   minY: number,
@@ -43,6 +45,13 @@ export type Bounds = readonly [
   maxY: number,
 ];
 
+export type SceneBounds = readonly [
+  sceneX: number,
+  sceneY: number,
+  sceneX2: number,
+  sceneY2: number,
+];
+
 export class ElementBounds {
   private static boundsCache = new WeakMap<
     ExcalidrawElement,
@@ -879,3 +888,21 @@ export const getCommonBoundingBox = (
     midY: (minY + maxY) / 2,
   };
 };
+
+/**
+ * returns scene coords of user's editor viewport (visible canvas area) bounds
+ */
+export const getVisibleSceneBounds = ({
+  scrollX,
+  scrollY,
+  width,
+  height,
+  zoom,
+}: AppState): SceneBounds => {
+  return [
+    -scrollX,
+    -scrollY,
+    -scrollX + width / zoom.value,
+    -scrollY + height / zoom.value,
+  ];
+};

packages/excalidraw/index.tsx

@@ -249,7 +249,7 @@ export { TTDDialogTrigger } from "./components/TTDDialog/TTDDialogTrigger";
 export { normalizeLink } from "./data/url";
 export { zoomToFitBounds } from "./actions/actionCanvas";
 export { convertToExcalidrawElements } from "./data/transform";
-export { getCommonBounds } from "./element/bounds";
+export { getCommonBounds, getVisibleSceneBounds } from "./element/bounds";
 
 export {
   elementsOverlappingBBox,