feat: add view mode in Excalidraw (#2840)

Co-authored-by: Lipis <lipiridis@gmail.com>

src/actions/actionToggleViewMode.tsx

@@ -0,0 +1,22 @@
+import { CODES, KEYS } from "../keys";
+import { register } from "./register";
+import { trackEvent } from "../analytics";
+
+export const actionToggleViewMode = register({
+  name: "viewMode",
+  perform(elements, appState) {
+    trackEvent("view", "mode", "view");
+    return {
+      appState: {
+        ...appState,
+        viewModeEnabled: !this.checked!(appState),
+        selectedElementIds: {},
+      },
+      commitToHistory: false,
+    };
+  },
+  checked: (appState) => appState.viewModeEnabled,
+  contextItemLabel: "labels.viewMode",
+  keyTest: (event) =>
+    !event[KEYS.CTRL_OR_CMD] && event.altKey && event.code === CODES.R,
+});

src/actions/manager.tsx

@@ -7,11 +7,11 @@ import {
   ActionResult,
 } from "./types";
 import { ExcalidrawElement } from "../element/types";
-import { AppState } from "../types";
+import { AppState, ExcalidrawProps } from "../types";
 
 // This is the <App> component, but for now we don't care about anything but its
 // `canvas` state.
-type App = { canvas: HTMLCanvasElement | null };
+type App = { canvas: HTMLCanvasElement | null; props: ExcalidrawProps };
 
 export class ActionManager implements ActionsManagerInterface {
   actions = {} as ActionsManagerInterface["actions"];
@@ -66,6 +66,12 @@ export class ActionManager implements ActionsManagerInterface {
     if (data.length === 0) {
       return false;
     }
+    const { viewModeEnabled } = this.getAppState();
+    if (viewModeEnabled) {
+      if (data[0].name !== "viewMode") {
+        return false;
+      }
+    }
 
     event.preventDefault();
     this.updater(

src/actions/shortcuts.ts

@@ -22,7 +22,8 @@ export type ShortcutName =
   | "gridMode"
   | "zenMode"
   | "stats"
-  | "addToLibrary";
+  | "addToLibrary"
+  | "viewMode";
 
 const shortcutMap: Record<ShortcutName, string[]> = {
   cut: [getShortcutKey("CtrlOrCmd+X")],
@@ -56,6 +57,7 @@ const shortcutMap: Record<ShortcutName, string[]> = {
   zenMode: [getShortcutKey("Alt+Z")],
   stats: [],
   addToLibrary: [],
+  viewMode: [getShortcutKey("Alt+R")],
 };
 
 export const getShortcutFromShortcutName = (name: ShortcutName) => {

src/actions/types.ts

@@ -84,7 +84,8 @@ export type ActionName =
   | "alignVerticallyCentered"
   | "alignHorizontallyCentered"
   | "distributeHorizontally"
-  | "distributeVertically";
+  | "distributeVertically"
+  | "viewMode";
 
 export interface Action {
   name: ActionName;