workspaceThumbnails: allow requesting size at any time

The slide of thumbnailWorkspace is shown when entering overview,
connecting to the same signal that creates the thumbnails, the showing
signal of overview, but, to make the slide animation we need to know how
much width the slider has.  To do that we ask the thumbnailsWorkspace
about its width, but given that it connects to the same signal it could
ask the width without having created the thumbnails yet, so reporting a
width of 0 and confusing the slide animation.

Currently it works because gjs calls the callbacks following the order
of the clients connecting that signal, and the thumbnailsWorskpace is
connected before the slide ones.

To avoid that we allow to request the preferred size of the
thumbnailsBox at any time with any number of thumbnails. The only thing
required is to make sure the porthole is accessible when requesting the
preferred size.

https://bugzilla.gnome.org/show_bug.cgi?id=732901

diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index 14091a557e66c5ef41aea25acf3b064d5e587825..c11d13bd16b8100c5ef854fe1bf47d8f5e38751d 100644 (file)
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -878,9 +878,6 @@ const ThumbnailsBox = new Lang.Class({
         for (let key in ThumbnailState)
             this._stateCounts[ThumbnailState[key]] = 0;
 
-        // The "porthole" is the portion of the screen that we show in the workspaces
-        this._porthole = Main.layoutManager.getWorkAreaForMonitor(Main.layoutManager.primaryIndex);
-
         this.addThumbnails(0, global.screen.n_workspaces);
 
         this._updateSwitcherVisibility();
@@ -904,6 +901,7 @@ const ThumbnailsBox = new Lang.Class({
         for (let w = 0; w < this._thumbnails.length; w++)
             this._thumbnails[w].destroy();
         this._thumbnails = [];
+        this._porthole = null;
     },
 
     _workspacesChanged: function() {
@@ -934,6 +932,7 @@ const ThumbnailsBox = new Lang.Class({
     },
 
     addThumbnails: function(start, count) {
+        this._ensurePorthole();
         for (let k = start; k < start + count; k++) {
             let metaWorkspace = global.screen.get_workspace_by_index(k);
             let thumbnail = new WorkspaceThumbnail(metaWorkspace);
@@ -1121,9 +1120,7 @@ const ThumbnailsBox = new Lang.Class({
         // the size request to our children because we know how big they are and know
         // that the actors aren't depending on the virtual functions being called.
 
-        if (this._thumbnails.length == 0)
-            return;
-
+        this._ensurePorthole();
         let themeNode = this.actor.get_theme_node();
 
         let spacing = themeNode.get_length('spacing');
@@ -1135,8 +1132,7 @@ const ThumbnailsBox = new Lang.Class({
     },
 
     _getPreferredWidth: function(actor, forHeight, alloc) {
-        if (this._thumbnails.length == 0)
-            return;
+        this._ensurePorthole();
 
         let themeNode = this.actor.get_theme_node();
 
@@ -1154,6 +1150,13 @@ const ThumbnailsBox = new Lang.Class({
         alloc.natural_size = width;
     },
 
+    // The "porthole" is the portion of the screen that we show in the
+    // workspaces
+    _ensurePorthole: function() {
+        if (!this._porthole)
+            this._porthole = Main.layoutManager.getWorkAreaForMonitor(Main.layoutManager.primaryIndex);
+    },
+
     _allocate: function(actor, box, flags) {
         let rtl = (Clutter.get_default_text_direction () == Clutter.TextDirection.RTL);