[libhandy] tab: Stop spinner when not visible

[Adrien Plazas <aplazas src gnome org>]

commit 3e33f2aef3b0ead3fd26df9f4d0b8869cd63c0b5
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Mon Feb 8 16:06:55 2021 +0500

    tab: Stop spinner when not visible
    
    Surprisingly, an active spinner still uses CPU when not mapped. Stopping
    it significantly reduces CPU usage.

 src/hdy-tab.c  | 39 +++++++++++++++++++++++++++++++++++++++
 src/hdy-tab.ui |  3 +--
 2 files changed, 40 insertions(+), 2 deletions(-)
---
diff --git a/src/hdy-tab.c b/src/hdy-tab.c
index 4e80b628..2b117237 100644
--- a/src/hdy-tab.c
+++ b/src/hdy-tab.c
@@ -29,6 +29,7 @@ struct _HdyTab
   GtkWidget *title;
   GtkWidget *icon_stack;
   GtkImage *icon;
+  GtkSpinner *spinner;
   GtkImage *indicator_icon;
   GtkWidget *indicator_btn;
   GtkWidget *close_btn;
@@ -185,6 +186,19 @@ update_title (HdyTab *self)
   update_tooltip (self);
 }
 
+static void
+update_spinner (HdyTab *self)
+{
+  gboolean loading = self->page && hdy_tab_page_get_loading (self->page);
+  gboolean mapped = gtk_widget_get_mapped (GTK_WIDGET (self));
+
+  /* Don't use CPU when not needed */
+  if (loading && mapped)
+    gtk_spinner_start (self->spinner);
+  else
+    gtk_spinner_stop (self->spinner);
+}
+
 static void
 update_icons (HdyTab *self)
 {
@@ -226,6 +240,7 @@ static void
 update_loading (HdyTab *self)
 {
   update_icons (self);
+  update_spinner (self);
   set_style_class (GTK_WIDGET (self), "loading",
                    hdy_tab_page_get_loading (self->page));
 }
@@ -583,6 +598,26 @@ hdy_tab_unrealize (GtkWidget *widget)
   self->window = NULL;
 }
 
+static void
+hdy_tab_map (GtkWidget *widget)
+{
+  HdyTab *self = HDY_TAB (widget);
+
+  GTK_WIDGET_CLASS (hdy_tab_parent_class)->map (widget);
+
+  update_spinner (self);
+}
+
+static void
+hdy_tab_unmap (GtkWidget *widget)
+{
+  HdyTab *self = HDY_TAB (widget);
+
+  GTK_WIDGET_CLASS (hdy_tab_parent_class)->unmap (widget);
+
+  update_spinner (self);
+}
+
 static gint
 get_end_padding (HdyTab *self)
 {
@@ -857,6 +892,8 @@ hdy_tab_class_init (HdyTabClass *klass)
   widget_class->size_allocate = hdy_tab_size_allocate;
   widget_class->realize = hdy_tab_realize;
   widget_class->unrealize = hdy_tab_unrealize;
+  widget_class->map = hdy_tab_map;
+  widget_class->unmap = hdy_tab_unmap;
   widget_class->draw = hdy_tab_draw;
   widget_class->direction_changed = hdy_tab_direction_changed;
 
@@ -920,6 +957,7 @@ hdy_tab_class_init (HdyTabClass *klass)
   gtk_widget_class_bind_template_child (widget_class, HdyTab, title);
   gtk_widget_class_bind_template_child (widget_class, HdyTab, icon_stack);
   gtk_widget_class_bind_template_child (widget_class, HdyTab, icon);
+  gtk_widget_class_bind_template_child (widget_class, HdyTab, spinner);
   gtk_widget_class_bind_template_child (widget_class, HdyTab, indicator_icon);
   gtk_widget_class_bind_template_child (widget_class, HdyTab, indicator_btn);
   gtk_widget_class_bind_template_child (widget_class, HdyTab, close_btn);
@@ -979,6 +1017,7 @@ hdy_tab_set_page (HdyTab     *self,
     update_state (self);
     update_title (self);
     update_tooltip (self);
+    update_spinner (self);
     update_icons (self);
     update_indicator (self);
     update_needs_attention (self);
diff --git a/src/hdy-tab.ui b/src/hdy-tab.ui
index 634f6d55..7f79a33b 100644
--- a/src/hdy-tab.ui
+++ b/src/hdy-tab.ui
@@ -37,9 +37,8 @@
           </packing>
         </child>
         <child>
-          <object class="GtkSpinner">
+          <object class="GtkSpinner" id="spinner">
             <property name="visible">True</property>
-            <property name="active">True</property>
           </object>
           <packing>
             <property name="name">spinner</property>