From: Sebastian Keller <skeller@gnome.org>
Date: Tue, 11 May 2021 14:43:37 +0000 (+0200)
Subject: altTab: Avoid allocation cycle when showing CyclerHighlight
X-Git-Tag: archive/raspbian/50.5-1+rpi1~1^2~616^2^2~10
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=0a7507c617c08dbbccb4549665b87cf340f97e1c;p=gnome-shell.git

altTab: Avoid allocation cycle when showing CyclerHighlight

CyclerHighlight was showing and resizing one of its child widgets when
its own allocation was changed, queuing another relayout, resulting in
allocation cycle warnings. Avoid this by updating the size of the
highlight when the frame rect of window has changes rather than the size
of the CyclerHighlight actor itself.

Related: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4167
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1842>
---

diff --git a/js/ui/altTab.js b/js/ui/altTab.js
index bc8b17fac..6af9380ed 100644
--- a/js/ui/altTab.js
+++ b/js/ui/altTab.js
@@ -402,6 +402,7 @@ class CyclerHighlight extends St.Widget {
     _init() {
         super._init({ layout_manager: new Clutter.BinLayout() });
         this._window = null;
+        this._sizeChangedId = 0;
 
         this._clone = new Clutter.Clone();
         this.add_actor(this._clone);
@@ -415,7 +416,6 @@ class CyclerHighlight extends St.Widget {
 
         this.add_constraint(constraint);
 
-        this.connect('notify::allocation', this._onAllocationChanged.bind(this));
         this.connect('destroy', this._onDestroy.bind(this));
     }
 
@@ -423,6 +423,9 @@ class CyclerHighlight extends St.Widget {
         if (this._window == w)
             return;
 
+        if (this._sizeChangedId)
+            this._window.disconnect(this._sizeChangedId);
+
         this._window = w;
 
         if (this._clone.source)
@@ -434,21 +437,27 @@ class CyclerHighlight extends St.Widget {
             windowActor.hide();
 
         this._clone.source = windowActor;
-    }
 
-    _onAllocationChanged() {
-        if (!this._window) {
+        if (this._window) {
+            this._onSizeChanged();
+            this._sizeChangedId = this._window.connect('size-changed',
+                this._onSizeChanged.bind(this));
+        } else {
             this._highlight.set_size(0, 0);
             this._highlight.hide();
-        } else {
-            let [x, y] = this.allocation.get_origin();
-            let rect = this._window.get_frame_rect();
-            this._highlight.set_size(rect.width, rect.height);
-            this._highlight.set_position(rect.x - x, rect.y - y);
-            this._highlight.show();
         }
     }
 
+    _onSizeChanged() {
+        const bufferRect = this._window.get_buffer_rect();
+        const rect = this._window.get_frame_rect();
+        this._highlight.set_size(rect.width, rect.height);
+        this._highlight.set_position(
+            rect.x - bufferRect.x,
+            rect.y - bufferRect.y);
+        this._highlight.show();
+    }
+
     _onDestroy() {
         this.window = null;
     }