[gnome-shell/wip/exalm/gestures2: 29/34] workspaceAnimation: Use window clones

[Marge Bot <marge-bot src gnome org>]

commit 9cf300c972b06a7dcb4a00cc360a95f8ba257197
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Thu Jul 4 23:15:15 2019 +0500

    workspaceAnimation: Use window clones
    
    Instead of reparenting windows, clone them. This will allow to properly
    support multi-monitor setups in subsequent commits.
    
    Block window mapping animation while the animation is running to prevent
    new windows appearing during the animation from being visible at the same
    time as their clones.
    
    Fixes https://gitlab.gnome.org/GNOME/mutter/issues/929
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1326>

 js/ui/workspaceAnimation.js | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)
---
diff --git a/js/ui/workspaceAnimation.js b/js/ui/workspaceAnimation.js
index 83370b2a3c..e01371c49c 100644
--- a/js/ui/workspaceAnimation.js
+++ b/js/ui/workspaceAnimation.js
@@ -37,12 +37,16 @@ class WorkspaceGroup extends Clutter.Actor {
     }
 
     _syncStacking() {
-        const windowActors = global.get_window_actors();
-        let lastSibling = null;
+        const windowActors = global.get_window_actors().filter(w =>
+            this._shouldShowWindow(w.meta_window));
+
+        let lastRecord;
 
         for (const windowActor of windowActors) {
-            this.set_child_above_sibling(windowActor, lastSibling);
-            lastSibling = windowActor;
+            const record = this._windowRecords.find(r => r.windowActor === windowActor);
+
+            this.set_child_above_sibling(record.clone, lastRecord ? lastRecord.clone : null);
+            lastRecord = record;
         }
     }
 
@@ -51,16 +55,18 @@ class WorkspaceGroup extends Clutter.Actor {
             this._shouldShowWindow(w.meta_window));
 
         for (const windowActor of windowActors) {
-            const record = {
-                windowActor,
-                parent: windowActor.get_parent(),
-            };
+            const clone = new Clutter.Clone({
+                source: windowActor,
+                x: windowActor.x,
+                y: windowActor.y,
+            });
+
+            this.add_child(clone);
 
-            record.parent.remove_child(windowActor);
-            this.add_child(windowActor);
-            windowActor.show();
+            const record = { windowActor, clone };
 
             record.windowDestroyId = windowActor.connect('destroy', () => {
+                clone.destroy();
                 this._windowRecords.splice(this._windowRecords.indexOf(record), 1);
             });
 
@@ -71,11 +77,7 @@ class WorkspaceGroup extends Clutter.Actor {
     _removeWindows() {
         for (const record of this._windowRecords) {
             record.windowActor.disconnect(record.windowDestroyId);
-            this.remove_child(record.windowActor);
-            record.parent.add_child(record.windowActor);
-
-            if (!this._workspace.active)
-                record.windowActor.hide();
+            record.clone.destroy();
         }
 
         this._windowRecords = [];