fix(desktop): re-apply UI zoom on show/restore, scoped to chat windows (supersedes #61245)

apps/desktop/electron/main.ts

@@ -4743,7 +4743,13 @@ function installPreviewShortcut(window) {
 // survives reloads/restarts) rather than a main-process JSON file. The main
 // process owns setZoomLevel, so we mirror each change into localStorage and
 // read it back on did-finish-load to re-apply after reloads or crash recovery.
-import { clampZoomLevel, percentToZoomLevel, ZOOM_STORAGE_KEY, zoomLevelToPercent } from './zoom'
+import {
+  clampZoomLevel,
+  installZoomReassertOnWindowEvents,
+  percentToZoomLevel,
+  ZOOM_STORAGE_KEY,
+  zoomLevelToPercent
+} from './zoom'
 
 function setAndPersistZoomLevel(window, zoomLevel) {
   if (!window || window.isDestroyed()) {
@@ -6507,10 +6513,21 @@ async function startHermes() {
 // security posture: external links open in the OS browser, in-app navigation
 // stays confined to the dev server / packaged file URL, and the preview /
 // devtools / zoom / context-menu affordances behave identically everywhere.
-function wireCommonWindowHandlers(win) {
+//
+// `zoom` is opt-out for the pet overlay: it sizes its own OS window to fit the
+// sprite in unzoomed CSS px (overlayWindowSize -> setBounds) and has its own
+// Alt+wheel scale, so inheriting the global UI zoom would render the mascot
+// larger than its window and crop it. Chat windows keep zoom on.
+function wireCommonWindowHandlers(win, { zoom = true }: { zoom?: boolean } = {}) {
   installPreviewShortcut(win)
   installDevToolsShortcut(win)
-  installZoomShortcuts(win)
+  if (zoom) {
+    installZoomShortcuts(win)
+    // Re-apply persisted zoom on show/restore (Windows drops webContents zoom on
+    // minimize/restore) and on first load (reloads / crash recovery).
+    installZoomReassertOnWindowEvents(win, () => restorePersistedZoomLevel(win))
+    win.webContents.once('did-finish-load', () => restorePersistedZoomLevel(win))
+  }
   installContextMenu(win)
   win.webContents.setWindowOpenHandler(details => {
     openExternalUrl(details.url)
@@ -6702,7 +6719,9 @@ function spawnPetOverlayWindow(bounds) {
     // Not supported everywhere — best effort.
   }
 
-  wireCommonWindowHandlers(win)
+  // Pet overlay opts out of global UI zoom (see wireCommonWindowHandlers): it
+  // owns its window-fit + scale, and inheriting zoom would crop the sprite.
+  wireCommonWindowHandlers(win, { zoom: false })
 
   win.once('ready-to-show', () => {
     if (!win.isDestroyed()) {
@@ -6893,7 +6912,8 @@ function createWindow() {
   }
 
   mainWindow.webContents.once('did-finish-load', () => {
-    restorePersistedZoomLevel(mainWindow)
+    // Zoom restore is handled by wireCommonWindowHandlers (shared with session
+    // windows); no need to reapply it here.
     broadcastBootProgress()
     sendWindowStateChanged()
     startHermes().catch(error => rememberLog(error.stack || error.message))

apps/desktop/electron/zoom.test.ts

@@ -5,9 +5,19 @@
  */
 
 import assert from 'node:assert/strict'
+import fs from 'node:fs'
+import path from 'node:path'
 import test from 'node:test'
+import { fileURLToPath } from 'node:url'
 
-import { clampZoomLevel, percentToZoomLevel, ZOOM_STORAGE_KEY, zoomLevelToPercent } from './zoom'
+import {
+  clampZoomLevel,
+  installZoomReassertOnWindowEvents,
+  percentToZoomLevel,
+  ZOOM_REASSERT_WINDOW_EVENTS,
+  ZOOM_STORAGE_KEY,
+  zoomLevelToPercent
+} from './zoom'
 
 test('storage key stays stable so persisted zoom survives upgrades', () => {
   assert.equal(ZOOM_STORAGE_KEY, 'hermes:desktop:zoomLevel')
@@ -53,3 +63,63 @@ test('extreme percentages clamp to the level bounds', () => {
   assert.equal(percentToZoomLevel(1), -9)
   assert.equal(percentToZoomLevel(1_000_000), 9)
 })
+
+test('installZoomReassertOnWindowEvents wires show and restore', () => {
+  const handlers = new Map()
+  const win = {
+    isDestroyed: () => false,
+    on(event, listener) {
+      handlers.set(event, listener)
+    }
+  }
+  let calls = 0
+  installZoomReassertOnWindowEvents(win, () => {
+    calls += 1
+  })
+
+  assert.deepEqual([...handlers.keys()], [...ZOOM_REASSERT_WINDOW_EVENTS])
+  handlers.get('show')()
+  handlers.get('restore')()
+  assert.equal(calls, 2)
+})
+
+test('installZoomReassertOnWindowEvents skips destroyed windows', () => {
+  const handlers = new Map()
+  let destroyed = false
+  const win = {
+    isDestroyed: () => destroyed,
+    on(event, listener) {
+      handlers.set(event, listener)
+    }
+  }
+  let calls = 0
+  installZoomReassertOnWindowEvents(win, () => {
+    calls += 1
+  })
+  destroyed = true
+  handlers.get('show')()
+  assert.equal(calls, 0)
+})
+
+// Source assertion (see windows-child-process.test.ts for the established
+// pattern): wireCommonWindowHandlers lives in the electron main entry with heavy
+// Electron deps, so we assert the wiring contract against source rather than
+// booting a BrowserWindow. Locks in that the pet overlay opts OUT of global UI
+// zoom while chat windows keep it — the whole reason this fix is scoped.
+test('pet overlay opts out of global UI zoom; chat windows keep it', () => {
+  const electronDir = path.dirname(fileURLToPath(import.meta.url))
+  const source = fs.readFileSync(path.join(electronDir, 'main.ts'), 'utf8').replace(/\r\n/g, '\n')
+
+  // The shared helper gates all zoom wiring behind an opt-out flag.
+  assert.match(source, /function wireCommonWindowHandlers\(win, \{ zoom = true \}/)
+
+  // The pet overlay window is the only caller that disables zoom.
+  assert.match(source, /wireCommonWindowHandlers\(win, \{ zoom: false \}\)/)
+
+  // Zoom restore now flows through the shared helper, so createWindow must not
+  // reassert it directly (that would double-fire and drift from session windows).
+  const finishLoad = source.indexOf("mainWindow.webContents.once('did-finish-load'")
+  assert.notEqual(finishLoad, -1, 'missing mainWindow did-finish-load handler')
+  const snippet = source.slice(finishLoad, finishLoad + 300)
+  assert.doesNotMatch(snippet, /restorePersistedZoomLevel\(mainWindow\)/)
+})

apps/desktop/electron/zoom.ts

@@ -31,3 +31,22 @@ export function percentToZoomLevel(percent) {
 
   return clampZoomLevel(Math.log(percent / 100) / Math.log(ZOOM_FACTOR_BASE))
 }
+
+// Chromium on Windows can drop webContents zoom when a BrowserWindow is minimized
+// and restored. Re-apply the persisted level on these lifecycle transitions.
+export const ZOOM_REASSERT_WINDOW_EVENTS = ['show', 'restore']
+
+export function installZoomReassertOnWindowEvents(win, reassert) {
+  if (!win?.on) {
+    return
+  }
+
+  for (const event of ZOOM_REASSERT_WINDOW_EVENTS) {
+    win.on(event, () => {
+      if (win.isDestroyed?.()) {
+        return
+      }
+      reassert()
+    })
+  }
+}