workspacesView: Add back overview transition

The transition was temporarily removed when switching to the new
workspace layout manager. Now everything is in place to reimplement
it with a combination of the layout manager's state adjustment and
the view's allocation.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1345

js/ui/workspace.js

@@ -636,7 +636,7 @@ var WorkspaceLayout = GObject.registerClass({
             // example if the container height is being animated, we want to
             // avoid animating the children allocations to make sure they
             // don't "lag behind" the other animation).
-            if (layoutChanged) {
+            if (layoutChanged && !Main.overview.animationInProgress) {
                 const transition = animateAllocation(child, childBox);
                 if (transition) {
                     windowInfo.currentTransition = transition;
@@ -1149,6 +1149,15 @@ class Workspace extends St.Widget {
     }
 
     zoomToOverview() {
+        const animate =
+            this.metaWorkspace === null || this.metaWorkspace.active;
+
+        const adj = this.layout_manager.stateAdjustment;
+        adj.value = 0;
+        adj.ease(1, {
+            duration: animate ? Overview.ANIMATION_TIME : 0,
+            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+        });
     }
 
     zoomFromOverview() {
@@ -1166,29 +1175,10 @@ class Workspace extends St.Widget {
         if (this.metaWorkspace !== null && !this.metaWorkspace.active)
             return;
 
-        // Position and scale the windows.
+        this.layout_manager.stateAdjustment.ease(0, {
-        for (let i = 0; i < this._windows.length; i++)
-            this._zoomWindowFromOverview(i);
-    }
-
-    _zoomWindowFromOverview(index) {
-        let clone = this._windows[index];
-        clone.hideOverlay(false);
-
-        if (clone.metaWindow.showing_on_its_workspace()) {
-            clone.ease({
-                opacity: 255,
             duration: Overview.ANIMATION_TIME,
             mode: Clutter.AnimationMode.EASE_OUT_QUAD,
         });
-        } else {
-            // The window is hidden, make it shrink and fade it out
-            clone.ease({
-                opacity: 0,
-                duration: Overview.ANIMATION_TIME,
-                mode: Clutter.AnimationMode.EASE_OUT_QUAD,
-            });
-        }
     }
 
     _onDestroy() {

js/ui/workspacesView.js

@@ -7,6 +7,7 @@ const Main = imports.ui.main;
 const SwipeTracker = imports.ui.swipeTracker;
 const Workspace = imports.ui.workspace;
 
+var { ANIMATION_TIME } = imports.ui.overview;
 var WORKSPACE_SWITCH_TIME = 250;
 var SCROLL_TIMEOUT_TIME = 150;
 
@@ -579,6 +580,14 @@ class WorkspacesDisplay extends St.Widget {
 
     animateFromOverview(fadeOnPrimary) {
         for (let i = 0; i < this._workspacesViews.length; i++) {
+            const { x, y, width, height } =
+                Main.layoutManager.getWorkAreaForMonitor(i);
+            this._workspacesViews[i].ease({
+                x, y, width, height,
+                duration: ANIMATION_TIME,
+                mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+            });
+
             let animationType;
             if (fadeOnPrimary && i == this._primaryIndex)
                 animationType = AnimationType.FADE;
@@ -707,7 +716,11 @@ class WorkspacesDisplay extends St.Widget {
         if (!primaryView)
             return;
 
-        primaryView.set(this._actualGeometry);
+        primaryView.ease({
+            ...this._actualGeometry,
+            duration: Main.overview.animationInProgress ? ANIMATION_TIME : 0,
+            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+        });
     }
 
     _onRestacked(overview, stackIndices) {