IJPL-58454 Implement selecting the main menu bar on Windows by pressing Alt

GitOrigin-RevId: 3058dfa79b65cbd98815eddf543fb51892186668

platform/platform-impl/resources/intellij.platform.ide.impl.xml

@@ -70,5 +70,11 @@
       defaultValue="60"
       description="The interval between too-small window size checks on Windows and attempts to restore the size. Set to zero to disable"
     />
+    <registryKey
+      key="ide.windows.main.menu.focus.on.alt"
+      defaultValue="false"
+      description="Enable Alt key to focus the main menu bar on Windows"
+      restartRequired="true"
+    />
   </extensions>
 </idea-plugin>

platform/platform-impl/src/com/intellij/ide/IdeEventQueue.kt

@@ -1287,7 +1287,9 @@ private class WindowsAltSuppressor : IdeEventQueue.NonLockedEventDispatcher {
     if (uiSettings == null ||
         !SystemInfoRt.isWindows ||
         !Registry.`is`("actionSystem.win.suppressAlt", true) ||
-        !(uiSettings.hideToolStripes || uiSettings.presentationMode)) {
+        // Need to handle Alt to show hidden tool stripes by double Alt or to focus the main menu
+        !(uiSettings.hideToolStripes || uiSettings.presentationMode) &&
+        !Registry.`is`("ide.windows.main.menu.focus.on.alt", false)) {
       return false
     }
 

platform/platform-impl/src/com/intellij/openapi/wm/impl/customFrameDecorations/header/toolbar/ExpandableMenu.kt

@@ -30,6 +30,8 @@ import java.awt.event.ComponentAdapter
 import java.awt.event.ComponentEvent
 import java.awt.event.MouseAdapter
 import java.awt.event.MouseEvent
+import javax.accessibility.AccessibleContext
+import javax.accessibility.AccessibleState
 import javax.swing.JComponent
 import javax.swing.JFrame
 import javax.swing.JLayeredPane
@@ -102,7 +104,7 @@ internal class ExpandableMenu(
     ideMenuHelper.updateUI()
   }
 
-  fun switchState(actionMenuToShow: ActionMenu? = null, itemInd: Int = 0) {
+  fun switchState(actionMenuToShow: ActionMenu? = null, itemInd: Int = 0, selectOnlyHeaderMenu: Boolean = false) {
     if (isShowing() && actionMenuToShow == null) {
       hideExpandedMenuBar()
       return
@@ -130,11 +132,11 @@ internal class ExpandableMenu(
 
     // The first menu usage has no selection in the menu. Fix it by invokeLater
     ApplicationManager.getApplication().invokeLater {
-      selectMenu(actionMenu = actionMenuToShow, itemInd = itemInd)
+      selectMenu(actionMenu = actionMenuToShow, itemInd = itemInd, selectOnlyHeaderMenu = selectOnlyHeaderMenu)
     }
   }
 
-  private fun selectMenu(actionMenu: ActionMenu? = null, itemInd: Int) {
+  private fun selectMenu(actionMenu: ActionMenu? = null, itemInd: Int, selectOnlyHeaderMenu: Boolean = false) {
     var menu = ideMenu.getMenu(itemInd)
     if (actionMenu != null) {
       for (m in ideMenu.rootMenuItems) {
@@ -148,8 +150,11 @@ internal class ExpandableMenu(
     menu ?: return
 
     val subElements = menu.popupMenu.subElements
-    if (subElements.isEmpty()) {
+    if (subElements.isEmpty() || selectOnlyHeaderMenu) {
       MenuSelectionManager.defaultManager().selectedPath = arrayOf<MenuElement>(ideMenu, menu)
+      ApplicationManager.getApplication().invokeLater {
+        menu.accessibleContext.firePropertyChange(AccessibleContext.ACCESSIBLE_STATE_PROPERTY, null, AccessibleState.SELECTED)
+      }
     }
     else {
       MenuSelectionManager.defaultManager().selectedPath = arrayOf<MenuElement>(ideMenu, menu, menu.popupMenu, subElements[0])

platform/platform-impl/src/com/intellij/platform/ide/menu/JMenuBasedIdeMenuBarHelper.kt

@@ -5,13 +5,42 @@ import com.intellij.ide.ui.UISettings
 import com.intellij.openapi.actionSystem.ActionGroup
 import com.intellij.openapi.actionSystem.ActionPlaces
 import com.intellij.openapi.actionSystem.impl.ActionMenu
+import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.util.SystemInfoRt
+import com.intellij.openapi.util.registry.Registry
 import com.intellij.openapi.wm.impl.IdeFrameDecorator
 import com.intellij.openapi.wm.impl.headertoolbar.MainMenuWithButton
 import com.intellij.openapi.wm.impl.headertoolbar.MergedMainMenu
+import com.intellij.ui.AppUIUtil
 import com.intellij.util.concurrency.ThreadingAssertions
+import com.intellij.util.ui.accessibility.ScreenReader
+import kotlinx.coroutines.job
+import java.awt.AWTEvent
+import java.awt.KeyEventPostProcessor
+import java.awt.KeyboardFocusManager
+import java.awt.Toolkit
+import java.awt.event.AWTEventListener
+import java.awt.event.InputEvent
+import java.awt.event.KeyEvent
+import java.awt.event.MouseEvent
+import javax.accessibility.AccessibleContext
+import javax.accessibility.AccessibleState
+import javax.swing.MenuElement
 import javax.swing.MenuSelectionManager
+import javax.swing.SwingUtilities
 
 internal class JMenuBasedIdeMenuBarHelper(flavor: IdeMenuFlavor, menuBar: IdeJMenuBar.JMenuBarImpl) : IdeMenuBarHelper(flavor, menuBar) {
+  init {
+    if (WinAltKeyProcessor.isEnabled()) {
+      WinAltKeyProcessor.register(this)
+      menuBar.coroutineScope.coroutineContext.job.invokeOnCompletion {
+        ApplicationManager.getApplication().invokeLater {
+          WinAltKeyProcessor.unregister(this)
+        }
+      }
+    }
+  }
+
   override fun isUpdateForbidden() = MenuSelectionManager.defaultManager().selectedPath.isNotEmpty()
 
   override suspend fun doUpdateVisibleActions(newVisibleActions: List<ActionGroup>, forceRebuild: Boolean) {
@@ -68,4 +97,125 @@ internal class JMenuBasedIdeMenuBarHelper(flavor: IdeMenuFlavor, menuBar: IdeJMe
       menuBar.frame.validate()
     }
   }
-}
+
+  internal fun activateMenu() {
+    val menuBarComponent = menuBar.component
+    if (menuBarComponent is MergedMainMenu) {
+      val mainMenuWithButton = menuBarComponent.parent as? MainMenuWithButton
+      if (mainMenuWithButton?.mainMenuButton?.button?.isShowing == true) {
+        mainMenuWithButton.mainMenuButton.expandableMenu?.switchState(selectOnlyHeaderMenu = true)
+        return
+      }
+    }
+
+    val ideMenuBar = menuBarComponent as? IdeJMenuBar ?: return
+    val firstMenu = ideMenuBar.rootMenuItems.firstOrNull() ?: return
+    MenuSelectionManager.defaultManager().selectedPath = arrayOf<MenuElement>(menuBarComponent, firstMenu)
+    ApplicationManager.getApplication().invokeLater {
+      firstMenu.accessibleContext.firePropertyChange(AccessibleContext.ACCESSIBLE_STATE_PROPERTY, null, AccessibleState.SELECTED)
+    }
+  }
+
+  internal fun shouldProcessAltRelease(e: KeyEvent): Boolean {
+    val menuBarComponent = menuBar.component
+    val visibleComponent = if (menuBarComponent.isShowing) menuBarComponent
+    else {
+      val button = ((menuBarComponent as? MergedMainMenu)?.parent as? MainMenuWithButton)?.mainMenuButton?.button
+      if (button?.isShowing == true) button else return false
+    }
+
+    val window = SwingUtilities.getWindowAncestor(visibleComponent) ?: return false
+    if (SwingUtilities.getWindowAncestor(e.component) != window && e.component != window) return false
+    if (MenuSelectionManager.defaultManager().selectedPath.isNotEmpty()) return false
+    if (ScreenReader.isActive() && AppUIUtil.isInFullScreen(window)) return false
+
+    return true
+  }
+
+}
+
+internal object WinAltKeyProcessor : KeyEventPostProcessor, AWTEventListener {
+  private val helpers = mutableListOf<JMenuBasedIdeMenuBarHelper>()
+  private var registered = false
+
+  private var altPressed = false
+  private var altPressedOnly = false
+
+  @JvmStatic
+  fun isEnabled(): Boolean = SystemInfoRt.isWindows && Registry.`is`("ide.windows.main.menu.focus.on.alt", false)
+
+  fun register(helper: JMenuBasedIdeMenuBarHelper) {
+    helpers.add(helper)
+    if (!registered) {
+      KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventPostProcessor(this)
+      Toolkit.getDefaultToolkit().addAWTEventListener(this, AWTEvent.MOUSE_EVENT_MASK)
+      registered = true
+    }
+  }
+
+  fun unregister(helper: JMenuBasedIdeMenuBarHelper) {
+    helpers.remove(helper)
+    if (helpers.isEmpty() && registered) {
+      KeyboardFocusManager.getCurrentKeyboardFocusManager().removeKeyEventPostProcessor(this)
+      Toolkit.getDefaultToolkit().removeAWTEventListener(this)
+      registered = false
+    }
+  }
+
+  override fun eventDispatched(event: AWTEvent) {
+    if (!isEnabled()) {
+      return
+    }
+
+    // Prevent focusing the menu when hold Alt + mouse click shortcuts are used
+    if (event is MouseEvent && event.id == MouseEvent.MOUSE_PRESSED && altPressed) {
+      altPressedOnly = false
+    }
+  }
+
+  override fun postProcessKeyEvent(e: KeyEvent): Boolean {
+    if (!isEnabled()) {
+      return false
+    }
+
+    if (e.keyCode != KeyEvent.VK_ALT) {
+      if (altPressed && e.id == KeyEvent.KEY_PRESSED) {
+        altPressedOnly = false
+      }
+      return false
+    }
+
+    val settings = UISettings.instanceOrNull
+    // To avoid conflicts with the double Alt shortcut to show hidden tool stripes
+    if (settings == null || settings.hideToolStripes || settings.presentationMode) {
+      return false
+    }
+
+    when (e.id) {
+      KeyEvent.KEY_PRESSED -> {
+        if (!altPressed) {
+          altPressed = true
+          altPressedOnly = true
+        }
+      }
+      KeyEvent.KEY_RELEASED -> {
+        if (altPressed && altPressedOnly
+            && e.modifiersEx and (InputEvent.SHIFT_DOWN_MASK or InputEvent.CTRL_DOWN_MASK or InputEvent.META_DOWN_MASK) == 0) {
+          for (helper in helpers) {
+            if (helper.shouldProcessAltRelease(e)) {
+              ApplicationManager.getApplication().invokeLater {
+                helper.activateMenu()
+              }
+              break
+            }
+          }
+        }
+
+        altPressed = false
+        altPressedOnly = false
+      }
+    }
+
+    return false
+  }
+}