[gnome-shell/wip/aday/app-grid-layout] workspace: Clip window previews

[Allan Day <allanday src gnome org>]

commit 3e185484f02a57a4c88f2a87d9f2917f401676c6
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Feb 17 11:09:31 2021 -0300

    workspace: Clip window previews
    
    Window previews can spill out of the container when their position in the
    session overflows the monitor boundaries. In the past, Workspace didn't have
    a visible background, and was (almost) always fullscreen, which would mask
    this particular problem. However, nowadays, it is very much noticeable when
    this situation happens.
    
    Clip the window previews container to its allocation when the overview state
    is bigger than WINDOW_PICKER. That is, between HIDDEN and WINDOW_PICKER states,
    inclusive, no clipping is applied.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1691>

 js/ui/workspace.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index 47f1c69f2b..b849771a62 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -991,6 +991,16 @@ class Workspace extends St.Widget {
             });
 
         this._overviewAdjustment = overviewAdjustment;
+        this._overviewStateId = overviewAdjustment.connect('notify::value', () => {
+            const overviewState = overviewAdjustment.value;
+
+            // We want windows not to spill out when the overview is in
+            // APP_GRID state, but HIDDEN and WINDOW_PICKER should allow
+            // them to eventually draw outside the workspace.
+            this._container.clip_to_allocation =
+                overviewState > OverviewControls.ControlsState.WINDOW_PICKER;
+        });
+
         this.monitorIndex = monitorIndex;
         this._monitor = Main.layoutManager.monitors[this.monitorIndex];
 
@@ -1241,6 +1251,11 @@ class Workspace extends St.Widget {
             this._layoutFrozenId = 0;
         }
 
+        if (this._overviewStateId > 0) {
+            this._overviewAdjustment.disconnect(this._overviewStateId);
+            delete this._overviewStateId;
+        }
+
         this._windows = [];
     }