visualizer-view: implement basic panning

There are lots of little things that need fixing, such as the
ticks positioning, and reusing surfaces as much as possible, but
this gets our "MVP" panning in place.

lib/resources/ui/sp-visualizer-view.ui

@@ -11,8 +11,13 @@
             <property name="visible">true</property>
           </object>
         </child>
+        <child>
+          <object class="GtkBox">
+            <property name="orientation">vertical</property>
+            <property name="visible">true</property>
             <child>
               <object class="GtkScrolledWindow">
+                <property name="hscrollbar-policy">external</property>
                 <property name="visible">true</property>
                 <property name="propagate-natural-height">true</property>
                 <child>
@@ -22,7 +27,21 @@
                 </child>
               </object>
             </child>
+            <child>
+              <object class="GtkScrollbar" id="scrollbar">
+                <property name="adjustment">scroll_adjustment</property>
+                <property name="orientation">horizontal</property>
+                <property name="visible">true</property>
+              </object>
+            </child>
+          </object>
+        </child>
       </object>
     </child>
   </template>
+  <object class="GtkAdjustment" id="scroll_adjustment">
+    <property name="lower">0.0</property>
+    <property name="upper">0.0</property>
+    <property name="value">0.0</property>
+  </object>
 </interface>

lib/sp-visualizer-view.c

@@ -29,10 +29,11 @@
 typedef struct
 {
   SpCaptureReader   *reader;
+  SpZoomManager     *zoom_manager;
 
   SpVisualizerList  *list;
+  GtkAdjustment     *scroll_adjustment;
   SpVisualizerTicks *ticks;
-  SpZoomManager     *zoom_manager;
 } SpVisualizerViewPrivate;
 
 enum {
@@ -84,6 +85,41 @@ sp_visualizer_view_row_removed (SpVisualizerView *self,
     g_signal_emit (self, signals [VISUALIZER_REMOVED], 0, widget);
 }
 
+static void
+sp_visualizer_view_set_time_range (SpVisualizerView *self,
+                                   gint64            begin_time,
+                                   gint64            end_time)
+{
+  SpVisualizerViewPrivate *priv = sp_visualizer_view_get_instance_private (self);
+
+  g_assert (SP_IS_VISUALIZER_VIEW (self));
+
+  if (begin_time < end_time)
+    {
+      gint64 tmp = begin_time;
+      begin_time = end_time;
+      end_time = tmp;
+    }
+
+  sp_visualizer_list_set_time_range (priv->list, begin_time, end_time);
+  sp_visualizer_ticks_set_time_range (priv->ticks, begin_time, end_time);
+}
+
+static void
+sp_visualizer_view_adjustment_value_changed (SpVisualizerView *self,
+                                             GtkAdjustment    *adjustment)
+{
+  gint64 begin_time;
+  gint64 end_time;
+
+  g_assert (SP_IS_VISUALIZER_VIEW (self));
+  g_assert (GTK_IS_ADJUSTMENT (adjustment));
+
+  begin_time = gtk_adjustment_get_value (adjustment);
+  end_time = begin_time + gtk_adjustment_get_page_size (adjustment);
+  sp_visualizer_view_set_time_range (self, begin_time, end_time);
+}
+
 static void
 sp_visualizer_view_notify_zoom (SpVisualizerView *self,
                                 GParamSpec       *pspec,
@@ -104,8 +140,8 @@ sp_visualizer_view_notify_zoom (SpVisualizerView *self,
 
   end_time = begin_time + (NSEC_PER_SEC * 60.0 / zoom);
 
-  sp_visualizer_list_set_time_range (priv->list, begin_time, end_time);
+  sp_visualizer_view_set_time_range (self, begin_time, end_time);
-  sp_visualizer_ticks_set_time_range (priv->ticks, begin_time, end_time);
+  gtk_adjustment_set_page_size (priv->scroll_adjustment, end_time - begin_time);
 }
 
 static void
@@ -210,6 +246,7 @@ sp_visualizer_view_class_init (SpVisualizerViewClass *klass)
 
   gtk_widget_class_set_template_from_resource (widget_class, "/org/gnome/sysprof/ui/sp-visualizer-view.ui");
   gtk_widget_class_bind_template_child_private (widget_class, SpVisualizerView, list);
+  gtk_widget_class_bind_template_child_private (widget_class, SpVisualizerView, scroll_adjustment);
   gtk_widget_class_bind_template_child_private (widget_class, SpVisualizerView, ticks);
 
   gtk_widget_class_set_css_name (widget_class, "visualizers");
@@ -233,6 +270,12 @@ sp_visualizer_view_init (SpVisualizerView *self)
                            G_CALLBACK (sp_visualizer_view_row_removed),
                            self,
                            G_CONNECT_SWAPPED);
+
+  g_signal_connect_object (priv->scroll_adjustment,
+                           "value-changed",
+                           G_CALLBACK (sp_visualizer_view_adjustment_value_changed),
+                           self,
+                           G_CONNECT_SWAPPED);
 }
 
 /**
@@ -261,9 +304,24 @@ sp_visualizer_view_set_reader (SpVisualizerView *self,
   if (priv->reader != reader)
     {
       g_clear_pointer (&priv->reader, sp_capture_reader_unref);
-      priv->reader = sp_capture_reader_ref (reader);
       g_object_notify_by_pspec (G_OBJECT (self), properties [PROP_READER]);
       sp_visualizer_list_set_reader (priv->list, reader);
+      if (reader != NULL)
+        {
+          gint64 begin_time = 0;
+          gint64 end_time = 0;
+
+          priv->reader = sp_capture_reader_ref (reader);
+          begin_time = sp_capture_reader_get_start_time (reader);
+          end_time = sp_capture_reader_get_end_time (reader);
+
+          g_object_set (priv->scroll_adjustment,
+                        "lower", (gdouble)begin_time,
+                        "upper", (gdouble)end_time,
+                        "value", (gdouble)begin_time,
+                        NULL);
+        }
+
       if (priv->zoom_manager != NULL)
         sp_visualizer_view_notify_zoom (self, NULL, priv->zoom_manager);
     }