[gnome-shell/wip/aday/app-grid-layout] workspace: Move window previews to a child container

[Allan Day <allanday src gnome org>]

commit bfcd53ccca1b5d89acc0a51e7c26c2721e0fb353
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Feb 17 10:36:36 2021 -0300

    workspace: Move window previews to a child container
    
    Currently, Workspace is a single actor that contains both the background,
    and all window previews, and is managed by WorkspaceLayout. In the future,
    this concentrating aspect of it will bite us; we want the window previews
    to be clipped to the allocation, but not the background, since it will
    have shadows.
    
    Make Workspace subclass St.Widget with a ClutterBinLayout as layout manager,
    and move window previews to a child actor. To reduce the impact of this
    extra actor, it's a ClutterActor instead of a StWidget, and the spacing is
    still set on Workspace itself.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1691>

 js/ui/workspace.js | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index fd5d57f4c5..fa66417e37 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -975,14 +975,22 @@ class Workspace extends St.Widget {
         super._init({
             style_class: 'window-picker',
             pivot_point: new Graphene.Point({ x: 0.5, y: 0.5 }),
-            layout_manager: new WorkspaceLayout(metaWorkspace, monitorIndex),
+            layout_manager: new Clutter.BinLayout(),
+        });
+
+        const layoutManager = new WorkspaceLayout(metaWorkspace, monitorIndex);
+        this._container = new Clutter.Actor({
             reactive: true,
+            x_expand: true,
+            y_expand: true,
         });
+        this._container.layout_manager = layoutManager;
+        this.add_child(this._container);
 
         this.metaWorkspace = metaWorkspace;
         this._activeWorkspaceChangedId =
             this.metaWorkspace?.connect('notify::active', () => {
-                this.layoutManager.syncOverlays();
+                layoutManager.syncOverlays();
             });
 
         this._overviewAdjustment = overviewAdjustment;
@@ -994,7 +1002,7 @@ class Workspace extends St.Widget {
 
         // Background
         this._background = new WorkspaceBackground(monitorIndex);
-        this.layout_manager.setBackground(this._background);
+        layoutManager.setBackground(this._background);
 
         const clickAction = new Clutter.ClickAction();
         clickAction.connect('clicked', action => {
@@ -1009,7 +1017,7 @@ class Workspace extends St.Widget {
             }
         });
         this.bind_property('mapped', clickAction, 'enabled', GObject.BindingFlags.SYNC_CREATE);
-        this.add_action(clickAction);
+        this._container.add_action(clickAction);
 
         this.connect('style-changed', this._onStyleChanged.bind(this));
         this.connect('destroy', this._onDestroy.bind(this));
@@ -1051,7 +1059,7 @@ class Workspace extends St.Widget {
     }
 
     vfunc_get_focus_chain() {
-        return this.layout_manager.getFocusChain();
+        return this._container.layout_manager.getFocusChain();
     }
 
     _lookupIndex(metaWindow) {
@@ -1067,7 +1075,7 @@ class Workspace extends St.Widget {
     }
 
     syncStacking(stackIndices) {
-        this.layout_manager.syncStacking(stackIndices);
+        this._container.layout_manager.syncStacking(stackIndices);
     }
 
     _doRemoveWindow(metaWin) {
@@ -1082,7 +1090,7 @@ class Workspace extends St.Widget {
         // around while the user is interacting with the workspace, we delay
         // the positioning until the pointer remains still for at least 750 ms
         // or is moved outside the workspace
-        this.layout_manager.layout_frozen = true;
+        this._container.layout_manager.layout_frozen = true;
 
         if (this._layoutFrozenId > 0) {
             GLib.source_remove(this._layoutFrozenId);
@@ -1107,7 +1115,7 @@ class Workspace extends St.Widget {
                     return GLib.SOURCE_CONTINUE;
                 }
 
-                this.layout_manager.layout_frozen = false;
+                this._container.layout_manager.layout_frozen = false;
                 this._layoutFrozenId = 0;
                 return GLib.SOURCE_REMOVE;
             });
@@ -1171,7 +1179,7 @@ class Workspace extends St.Widget {
         if (this._layoutFrozenId > 0) {
             // If a window was closed before, unfreeze the layout to ensure
             // the new window is immediately shown
-            this.layout_manager.layout_frozen = false;
+            this._container.layout_manager.layout_frozen = false;
 
             GLib.source_remove(this._layoutFrozenId);
             this._layoutFrozenId = 0;
@@ -1217,7 +1225,7 @@ class Workspace extends St.Widget {
             this._layoutFrozenId = 0;
         }
 
-        this.layout_manager.layout_frozen = true;
+        this._container.layout_manager.layout_frozen = true;
         this._overviewHiddenId = Main.overview.connect('hidden', this._doneLeavingOverview.bind(this));
     }
 
@@ -1244,11 +1252,11 @@ class Workspace extends St.Widget {
     }
 
     _doneLeavingOverview() {
-        this.layout_manager.layout_frozen = false;
+        this._container.layout_manager.layout_frozen = false;
     }
 
     _doneShowingOverview() {
-        this.layout_manager.layout_frozen = false;
+        this._container.layout_manager.layout_frozen = false;
     }
 
     _isMyWindow(window) {
@@ -1292,7 +1300,7 @@ class Workspace extends St.Widget {
             this._doRemoveWindow(metaWindow);
         });
 
-        this.layout_manager.addWindow(clone, metaWindow);
+        this._container.layout_manager.addWindow(clone, metaWindow);
 
         if (this._windows.length == 0)
             clone.setStackAbove(this._background);
@@ -1311,14 +1319,14 @@ class Workspace extends St.Widget {
         if (index == -1)
             return null;
 
-        this.layout_manager.removeWindow(this._windows[index]);
+        this._container.layout_manager.removeWindow(this._windows[index]);
 
         return this._windows.splice(index, 1).pop();
     }
 
     _onStyleChanged() {
         const themeNode = this.get_theme_node();
-        this.layout_manager.spacing = themeNode.get_length('spacing');
+        this._container.layout_manager.spacing = themeNode.get_length('spacing');
     }
 
     _onCloneSelected(clone, time) {
@@ -1379,6 +1387,6 @@ class Workspace extends St.Widget {
     }
 
     get stateAdjustment() {
-        return this.layout_manager.stateAdjustment;
+        return this._container.layout_manager.stateAdjustment;
     }
 });