Add cloned shadow behind the window when swiching workspace on Desktop

@imports/ui/workspaceAnimation.d.ts

@@ -1,15 +1,16 @@
 import { Window, WindowActor } from 'gi://Meta'
 import { Actor, Clone } from 'gi://Clutter'
+import * as St from 'gi://St'
 
 export class WorkspaceAnimationController {
     _movingWindow: Window;
     _switchData: {
-        monitors: any[];
-        gestureActivated: boolean;
-        inProgress: boolean;
+        monitors: MonitorGroup[];
     };
     _swipeTracker: any;
     _prepareWorkspaceSwitch(workspaceIndices: Array<number>): void;
+    _finishWorkspaceSwitch(switchData: typeof this._switchData): void;
+
 }
 
 export class WorkspaceGroup extends Actor {
@@ -22,3 +23,7 @@ export class WorkspaceGroup extends Actor {
     _syncStacking(): void;
     _shouldShowWindow(win: Window): boolean;
 }
+
+export class MonitorGroup extends St.Widget {
+    _workspaceGroups: WorkspaceGroup []
+}

src/extension.ts

@@ -9,6 +9,7 @@ import * as GObject from 'gi://GObject'
 import { WindowPreview } from 'resource:///org/gnome/shell/ui/windowPreview.js'
 import { overview, layoutManager } from 'resource:///org/gnome/shell/ui/main.js'
 import { Extension } from 'resource:///org/gnome/shell/extensions/extension.js'
+import { WorkspaceAnimationController } from 'resource:///org/gnome/shell/ui/workspaceAnimation.js'
 
 // local modules
 import { constants } from './utils/constants.js'
@@ -31,6 +32,8 @@ import { global } from '@global'
 export default class RoundedWindowCorners extends Extension {
   // The methods of gnome-shell to monkey patch
   private _orig_add_window!: (_: Meta.Window) => void
+  private _orig_prep_worksapce_swt!: (workspaceIndices: number[]) => void
+  private _orig_finish_workspace_swt!: typeof WorkspaceAnimationController.prototype._finishWorkspaceSwitch
 
   private _services: Services | null = null
   private _window_actor_tracker: WindowActorTracker | null = null
@@ -41,6 +44,10 @@ export default class RoundedWindowCorners extends Extension {
     // Restore original methods, those methods will be restore when
     // extensions is disabled
     this._orig_add_window = WindowPreview.prototype._addWindow
+    this._orig_prep_worksapce_swt =
+      WorkspaceAnimationController.prototype._prepareWorkspaceSwitch
+    this._orig_finish_workspace_swt =
+      WorkspaceAnimationController.prototype._finishWorkspaceSwitch
 
     this._services = new Services ()
     this._window_actor_tracker = new WindowActorTracker ()
@@ -210,6 +217,83 @@ export default class RoundedWindowCorners extends Extension {
       })
     }
 
+    // Just Like the monkey patch when enter overview, need to add cloned shadow
+    // actor when switching workspaces on Desktop
+    WorkspaceAnimationController.prototype._prepareWorkspaceSwitch = function (
+      workspaceIndices
+    ) {
+      self._orig_prep_worksapce_swt.apply (this, [workspaceIndices])
+      for (const monitor of this._switchData.monitors) {
+        for (const workspace of monitor._workspaceGroups) {
+          // Let shadow actor always behind the window clone actor when we
+          // switch workspace by Ctrl+Alt+Left/Right
+          //
+          // Fix #55
+          const restacked_id = global.display.connect ('restacked', () => {
+            workspace._windowRecords.forEach (({ clone }) => {
+              const shadow = (clone as WsAnimationActor)._shadow_clone
+              if (shadow) {
+                workspace.set_child_below_sibling (shadow, clone)
+              }
+            })
+          })
+          const destroy_id = workspace.connect ('destroy', () => {
+            global.display.disconnect (restacked_id)
+            workspace.disconnect (destroy_id)
+          })
+
+          workspace._windowRecords.forEach (({ windowActor: actor, clone }) => {
+            const win = actor.meta_window
+            const frame_rect = win.get_frame_rect ()
+            const shadow = (actor as ExtensionsWindowActor)
+              .__rwc_rounded_window_info?.shadow
+            const enabled = UI.get_rounded_corners_effect (actor)?.enabled
+            if (shadow && enabled) {
+              // Only create shadow actor when window should have rounded
+              // corners when switching workspace
+
+              // Copy shadow actor to workspace group, so that to see
+              // shadow when switching workspace
+              const shadow_clone = new Clutter.Clone ({ source: shadow })
+              const paddings =
+                constants.SHADOW_PADDING * UI.WindowScaleFactor (win)
+
+              shadow_clone.width = frame_rect.width + paddings * 2
+              shadow_clone.height = frame_rect.height + paddings * 2
+              shadow_clone.x = clone.x + frame_rect.x - actor.x - paddings
+              shadow_clone.y = clone.y + frame_rect.y - actor.y - paddings
+
+              // Should works well work Desktop Cube extensions
+              clone.connect (
+                'notify::translation-z',
+                () => (shadow_clone.translation_z = clone.translation_z - 0.05)
+              )
+
+              // Add reference shadow clone for clone actor, so that we
+              // can restack position of shadow when we need
+              ;(clone as WsAnimationActor)._shadow_clone = shadow_clone
+              clone.bind_property ('visible', shadow_clone, 'visible', 0)
+              workspace.insert_child_below (shadow_clone, clone)
+            }
+          })
+        }
+      }
+    }
+
+    WorkspaceAnimationController.prototype._finishWorkspaceSwitch = function (
+      switchData
+    ) {
+      for (const monitor of this._switchData.monitors) {
+        for (const workspace of monitor._workspaceGroups) {
+          workspace._windowRecords.forEach (({ clone }) => {
+            (clone as WsAnimationActor)._shadow_clone?.destroy ()
+            delete (clone as WsAnimationActor)._shadow_clone
+          })
+        }
+      }
+      self._orig_finish_workspace_swt.apply (this, [switchData])
+    }
+
     const c = connections.get ()
 
     // Gnome-shell will not disable extensions when _logout/shutdown/restart
@@ -243,6 +327,10 @@ export default class RoundedWindowCorners extends Extension {
   disable () {
     // Restore patched methods
     WindowPreview.prototype._addWindow = this._orig_add_window
+    WorkspaceAnimationController.prototype._prepareWorkspaceSwitch =
+      this._orig_prep_worksapce_swt
+    WorkspaceAnimationController.prototype._finishWorkspaceSwitch =
+      this._orig_finish_workspace_swt
 
     // Remove the item to open preferences page in background menu
     UI.RestoreBackgroundMenu ()
@@ -330,3 +418,5 @@ const OverviewShadowActor = GObject.registerClass (
     }
   }
 )
+
+type WsAnimationActor = Clutter.Actor & { _shadow_clone?: Clutter.Actor }